The direct answer
A $500 budget aimed at sales splits roughly $250 to Amazon ads, $100 to Facebook ads, and $150 to promo-site placements in the planner on this page, producing around 61,900 impressions and close to 780 clicks when every rate stays at its illustrative default. A list-growth goal moves the largest share to Facebook, while a rank-spike goal moves the largest share to promo placements. Those reach totals come from illustrative planning assumptions — a $12 Amazon CPM, a $9 Facebook CPM, $40 promo placements at 8,000 impressions each, and click rates between 0.3% and 2.0% — so treat them as comparison scaffolding rather than predictions of what any platform will deliver.
What this allocator actually decides
Most authors do not overspend on advertising because they pick the wrong platform. They overspend because they never assigned each dollar a job before opening the ad dashboards. The tool above forces that assignment by asking for three facts: the total dollars available for one push, the single outcome that matters most this month, and which of the three channels you will genuinely run. From those inputs it distributes the budget by goal weights, converts each share into spend, then converts spend into impressions and clicks with the illustrative rates printed beside every row.
The allocation step happens before the reach step. First the planner normalizes weights across the channels you left switched on, so turning one channel off hands its share to the survivors instead of deleting money. Then it rounds each share to cents and corrects penny drift on the largest channel, keeping the rows exactly equal to the total you typed. Only after the dollars balance does it estimate impressions and clicks, which means the spend split stays honest even when you disbelieve the reach math.
Read the output in that same order. Confirm the dollar split matches your intention, confirm the share percentages feel proportionate to your goal, and only then glance at impressions and clicks as a rough sense of scale. When a row surprises you, the cause sits in the weights or the toggles, not in the CPM column.
How the calculation works, step by step
The planner starts with a weight table keyed to your selected goal. Sales uses 50% Amazon, 20% Facebook, and 30% promo sites. List growth uses 20% Amazon, 55% Facebook, and 25% promo sites. A rank spike uses 30% Amazon, 15% Facebook, and 55% promo sites. These weights encode a judgment about where each outcome is easiest to buy: purchase intent concentrates on Amazon, inexpensive signup volume concentrates on Facebook, and concentrated download bursts concentrate in promo newsletters.
Suppose you enter $500 with the sales goal and leave all three channels enabled. The weights already sum to 100%, so no rescaling is needed. Amazon receives 500 × 0.50 = $250.00. Facebook receives 500 × 0.20 = $100.00. Promo sites receive 500 × 0.30 = $150.00. Add the three shares and you return to $500.00, which is the internal consistency check you should repeat whenever you change a toggle.
Disabling a channel triggers renormalization. Take the same $500 sales push but switch Facebook off. The surviving raw weights are 0.50 for Amazon and 0.30 for promo, summing to 0.80. Amazon's normalized share becomes 0.50 ÷ 0.80 = 62.5%, worth $312.50. Promo becomes 0.30 ÷ 0.80 = 37.5%, worth $187.50. Facebook drops to zero without dragging the total down. That behavior matters because many authors run only two channels; the planner should reallocate rather than leave 20% of the budget stranded.
Reach math follows spend math. Amazon impressions equal spend divided by $12, multiplied by 1,000. Facebook impressions equal spend divided by $9, multiplied by 1,000. Promo impressions equal promo spend divided by $40 per placement, multiplied by 8,000 illustrative impressions per placement. Clicks multiply each channel's rounded impressions by its illustrative click rate: 0.3% for Amazon, 1.1% for Facebook, and 2.0% for promo audiences.
Run the default $500 sales case through the reach formulas. Amazon: $250 ÷ $12 × 1,000 = 20,833 impressions, and 20,833 × 0.003 = 62 clicks after rounding. Facebook: $100 ÷ $9 × 1,000 = 11,111 impressions, and 11,111 × 0.011 = 122 clicks. Promo: $150 ÷ $40 × 8,000 = 30,000 impressions across three full placements, and 30,000 × 0.02 = 600 clicks. Total reach is 61,944 impressions and 784 clicks. Every one of those figures carries the word illustrative because the rates are placeholders you should eventually replace with your own history.
The list-growth default tells a different story with identical arithmetic. At $500, Amazon takes 20% ($100.00), Facebook takes 55% ($275.00), and promo takes 25% ($125.00). Amazon impressions become 8,333 with 25 clicks, Facebook becomes 30,556 impressions with 336 clicks, and promo becomes 25,000 impressions with 500 clicks, totaling 63,889 impressions and 861 clicks. Same budget, more clicks — because Facebook's lower CPM and higher click rate manufacture volume, which is exactly what a signup goal wants.
Worked numbers you can verify by hand
Grab a calculator and confirm the rank-spike default before trusting any other row. Enter $500, choose the rank goal, and keep all channels on. Amazon's 30% is $150.00, Facebook's 15% is $75.00, and promo's 55% is $275.00. Amazon impressions are 150 ÷ 12 × 1,000 = 12,500 with about 38 clicks. Facebook impressions are 75 ÷ 9 × 1,000 = 8,333 with about 92 clicks. Promo spend of $275 divides into six full $40 placements ($240) with $35 left over, and the impression formula gives 275 × 200 = 55,000 impressions with 1,100 clicks. The total is 75,833 impressions and roughly 1,230 clicks — the highest click count of the three goals because promo click assumptions run hot and promo owns the majority share.
Now test a two-channel case to see renormalization clearly. Enter $300, pick list growth, and switch promo sites off. Raw surviving weights are 0.20 Amazon and 0.55 Facebook, summing to 0.75. Amazon normalizes to 0.20 ÷ 0.75 = 26.67%, or $80.00. Facebook normalizes to 0.55 ÷ 0.75 = 73.33%, or $220.00. Impressions are 6,667 for Amazon and 24,444 for Facebook, totaling 31,111, with clicks near 20 and 269 respectively. Nothing vanishes; the $75 that would have gone to promo redistributes proportionally.
Try a budget that exposes placement rounding. Enter $90 with the sales goal and all channels on. Promo receives 30%, or $27.00, which buys zero full $40 placements — floor(27 ÷ 40) = 0 — yet the impression formula still credits 27 × 200 = 5,400 impressions. That fractional-placement treatment keeps small budgets continuous instead of cliff-edged, but you should read it as a warning: modeled impressions without a bookable placement are the planner telling you the budget cannot execute the plan. The tool flags totals under $100 for exactly this reason.
Illustrative hypothetical example: a debut novelist with $500 and a sales goal
Consider a hypothetical debut novelist — an illustrative scenario, not a report of any real campaign — launching a $4.99 mystery with no series behind it and $500 she can afford to lose. She selects the sales goal and leaves every channel on. The planner assigns $250 to Amazon, $100 to Facebook, and $150 to promo sites, projecting roughly 61,900 impressions and 784 clicks.
Her correct reading starts with the promo row. Three $40 placements consume $120 of the $150 promo share, leaving $30 that cannot book a fourth slot at the assumed fee. She should therefore treat the promo allocation as three placements plus a $30 reserve, and either bank the reserve toward a fourth placement or move it into Amazon. The Amazon row of $250 at roughly $25 per day across ten days gives her two or three ad groups enough daily volume to exit the learning phase, while the $100 Facebook row functions as a creative test: one image, one video, small audiences, kill the loser after $30.
What makes this example instructive is the sequencing it implies. She books the three promo placements on staggered dates first, because newsletter inventory sells out and dates anchor everything else. She launches Amazon ads three days before the first placement so click history exists when promo traffic arrives. She runs Facebook only during the promo week, retargeting engagers afterward if signup costs look acceptable. The planner never mentions dates, yet the allocation only works when the dollars arrive in that order.
If her actual Amazon CPM turns out to be $18 instead of the illustrative $12, her Amazon impressions fall from 20,833 to about 13,900 — a one-third haircut she absorbs by shifting $30 of reserve promo money into Amazon. That adjustment habit matters more than the opening split. The starting allocation is a hypothesis; the reallocation after three days of real costs is the strategy.
Illustrative hypothetical example: a nonfiction author with $400 and a list-growth goal
Now consider a hypothetical nonfiction author — again an illustrative scenario with invented numbers — offering a free productivity checklist in exchange for email signups, with a $997 course behind the list. He enters $400, selects list growth, and keeps all channels on. Normalized weights of 20%, 55%, and 25% produce $80 for Amazon, $220 for Facebook, and $100 for promo sites.
His funnel math differs completely from the novelist's. Facebook's $220 at a $9 illustrative CPM yields about 24,444 impressions and 269 clicks; if his landing page converts 30% of clicks to subscribers, that is roughly 81 new emails from Facebook alone. Amazon's $80 yields about 6,667 impressions and 20 clicks, but those clicks carry buyer intent and may purchase the $9.99 companion workbook directly. Promo's $100 buys two full placements with $20 left over, modeled at 20,000 impressions and 400 clicks — the largest click source on paper, though newsletter audiences convert to subscribers only when the freebie matches the newsletter's topic precisely.
His execution therefore inverts the novelist's. He leads with the Facebook signup test, spending $40 across two audiences before committing the remaining $180, because list cost per subscriber decides whether the course funnel survives. He treats the two promo placements as list accelerants scheduled after the landing page converts above 25%, never before. Amazon runs at maintenance level — exact-match keywords on his own title and two competitors — because its job is capturing demand, not manufacturing it.
The instructive contrast is the definition of waste. For the novelist, waste is promo placements without Amazon ads ready to catch browsing spillover. For this author, waste is promo placements driving traffic to an untested signup page. Same planner, same arithmetic, opposite failure mode — which is why the goal selector exists and why copying another author's split rarely works.
Why the goal selector changes everything
Sales, list growth, and rank behave like different products even when the book file is identical. A sales push must convert strangers into buyers within days, so it pays a premium for Amazon placement where carts already sit open. A list-growth push can wait months for payback through a sequence, so it buys the cheapest qualified attention available, usually on Facebook. A rank push needs compressed velocity — many transactions inside a short window — so it concentrates spend in newsletter placements whose audiences act on the same morning.
The default weights express those instincts numerically, but you should understand the reasoning well enough to override them. When your Amazon ads historically convert at triple your Facebook rate, shifting ten points of share from Facebook to Amazon is rational even under a list-growth goal, provided your signup form lives on a retailer-neutral page. When your newsletter placements repeatedly outperform paid social, promoting the rank weights into an ordinary sales launch can make sense during the first week. The planner gives you toggles and visible shares precisely so deviations stay deliberate.
Beginners often ask which single goal fits a first book. Unless a back-end product like a course or a rapid-release series exists, choose sales. Email sequences and rank campaigns both assume something worth harvesting later; a standalone debut without follow-up monetizes attention only at the register. Authors with three or more books in one series can justify list growth, because each subscriber's lifetime value spans multiple purchases. Authors stacking five or more promo placements inside one week can justify the rank goal, because the concentrated burst may trigger recommendation visibility that outlasts the spend.
Reading the reach estimates without fooling yourself
Every impression and click figure on this page descends from assumed rates, and assumed rates are the part of media planning most likely to embarrass you. A $12 Amazon CPM approximates a competitive category illustration, not a quote; real search-term CPMs swing with bid pressure, seasonality, and format. A $9 Facebook CPM similarly compresses an enormous range — broad audiences cost less, narrow author-interest stacks cost more, and creative fatigue raises costs week by week. The $40 promo placement with 8,000 impressions describes a mid-tier newsletter illustration, while actual placement fees span from $15 community swaps to several hundred dollars for large deal sites, with list responsiveness varying even more.
The 0.3% Amazon click rate, 1.1% Facebook click rate, and 2.0% promo click rate deserve equal skepticism. Amazon search ads earn clicks from shoppers who typed the keyword, so relevance dominates: a tight exact-match term can multiply the assumed rate while a loose auto campaign dilutes it. Facebook interrupts browsers, so the creative carries the outcome; thumb-stopping cover video beats static quotes by margins no planner can preset. Promo newsletters arrive with endorsement trust, which lifts clicks when the genre matches and collapses them when it does not — a romance audience shown a programming manual will not click at 2% no matter what the model says.
Use the estimates comparatively, never absolutely. The statement worth keeping is that $100 on Facebook buys roughly 11,100 illustrative impressions while $100 on Amazon buys roughly 8,300, a structural gap that persists across a wide band of real CPMs. The statement worth discarding is that either figure predicts your campaign. Replace the illustrative rates with your last thirty days of account data as soon as you have it: divide spend by impressions for your true CPMs, divide clicks by impressions for your true CTRs, and rerun the allocation with those numbers in a spreadsheet. The planner's split still guides where dollars go; your history guides what they return.
Edge cases and failure modes
Zero channels selected is the only input combination that breaks the math, and the planner answers it with a failure verdict rather than zeros. All weights normalize against a sum of zero, which is undefined, so the tool refuses to invent shares and instead asks you to enable at least one channel. Treat that message as a checklist: if you switched everything off while experimenting, switch your primary channel back on before reading further.
A $0 budget produces an informational verdict with visible shares but zero spend everywhere. That state is useful exactly once — when you want to preview the percentage split for a goal before committing dollars. Enter the goal, set your toggles, note the shares, then type a real total. Nobody should optimize reach figures at $0 because every downstream number is definitionally zero.
Totals under $100 trigger a thin-budget warning, and you should heed it rather than admire the three-way precision. A $60 plan that assigns $30 to Amazon, $12 to Facebook, and $18 to promo buys neither a testable ad sample nor a single full placement. Concentrate the entire amount in the channel matching your goal, run it for one week, and record the actual CPM and conversion rate. Diversification is a property of budgets large enough to survive being wrong in one channel.
Single-channel allocations earn their own warning even at healthy totals. Spending $500 entirely on Amazon simplifies management and measurement, but it abandons the audiences that never search Amazon first. The practical test is marginal: if your second channel's first $50 buys learning you cannot get from the first channel — different creative feedback, different keyword discovery, different placement dates — fund it. If the second $50 merely duplicates the first channel's audience, keep the concentration and revisit later.
Promo rounding deserves a dedicated caution. The impression formula scales continuously with promo spend, but real placements sell in $40-shaped indivisible units under the illustrative fee. A $55 promo share is one placement plus $15 of unusable remainder, not 1.375 placements. Always convert the promo dollar row into a whole placement count with floor division, then decide what the remainder does: accumulate toward another placement, subsidize creative production, or transfer into the auction channels. Authors who ignore the remainder wonder why their booked schedule never matches the plan.
Oversized budgets fail differently. At $10,000 the arithmetic still balances, but the assumptions behind it collapse: CPMs rise as you exhaust narrow audiences, click rates decay as frequency climbs, and promo inventory for a single title in a single week simply does not exist at that scale. The planner does not cap ambition, yet budgets above a few thousand dollars belong in a phased plan with weekly creative refreshes and audience expansion, not a single allocation. Split large totals into weekly tranches and reallocate between tranches using observed costs.
Finally, guard against goal drift mid-campaign. An allocation built for list growth that you judge on day-three sales will always look broken, because its Facebook-heavy split was never designed to maximize immediate purchases. Write the goal on paper before spending, evaluate only that goal for the first full week, and change goals only between budget tranches. The planner's weights are promises about what each dollar was hired to do; reassigning the job halfway through voids the comparison.
Genre-specific guidance
Romance rewards volume and punishes hesitation. Read-through across a series converts inexpensive clicks into multiple sales, so romance authors can justify the list-growth weighting even during launch week: Facebook prospecting fills the funnel while promo placements spike individual titles. Keep Amazon always on for romance, because also-bought visibility compounds across books, but let Facebook carry the plurality whenever cost per subscriber stays under a third of the series read-through margin.
Thriller and mystery audiences behave like romance readers with shorter memories. Promo placements punch above their weight because newsletter subscribers in these genres buy today rather than shelving for later. The rank-spike weighting fits thriller launches well: stack three to five placements inside ten days, support them with Amazon search defense on your own name and the series terms, and use Facebook narrowly for retargeting page visitors. Avoid broad Facebook prospecting until book two exists, since single-title thriller economics rarely survive cold-traffic acquisition.
Fantasy splits by subgenre. Romantasy overlaps romance mechanics — series completion matters, newsletter audiences respond, and Facebook creative featuring character art travels. Epic and hard fantasy skew toward Amazon, where sample downloads and series-page browsing do the persuading that interruption ads cannot. Map your allocation to tropes: romance-forward fantasy follows the romance paragraph, lore-forward fantasy follows the nonfiction paragraph below in spirit, weighting Amazon and promo over Facebook.
Science fiction resembles fantasy with an older, more male, more ad-blind audience on social platforms. Promo newsletters and Amazon search outperform Facebook prospecting for most indie science fiction, except when tie-in media or gaming crossovers supply ready-made interest targeting. Default to the sales weighting, keep Facebook experimental money under 20%, and measure success in sell-through to book two rather than click volume.
Nonfiction inverts fiction logic. The email list is the product and the book is the credential, so list-growth weighting is usually correct even when launch excitement tempts you toward rank. Facebook lead campaigns aimed at a specific painful problem outperform generic book awareness ads by wide margins. Use Amazon defensively — your title, your name, the two closest competing titles — and spend promo money only in topic-aligned newsletters, because a large mismatched audience converts at near zero regardless of click assumptions.
Memoir and literary fiction face the hardest paid-acquisition math on this page. Broad appeal without genre targeting raises CPMs and lowers conversion simultaneously. Small budgets work better concentrated in a single thematically aligned promo placement plus Amazon defense than scattered across three channels. Reserve Facebook for reader-magnet building around a universal theme — grief, migration, reinvention — rather than direct book sales, and judge the spend on subscriber quality instead of day-one royalties.
Children's, middle-grade, and young-adult books add a gatekeeper problem: the buyer and the reader are different people. Facebook reaches parents and educators efficiently, which supports list-growth weighting for teacher resources and activity kits. Amazon matters for gift-driven seasonal spikes. Promo newsletters help least here unless the placement specifically serves parents or librarians. Whatever the planner suggests, confirm the creative speaks to the purchaser, not only the young reader.
Timing, sequencing, and weekly management
An allocation is a snapshot; a campaign is a schedule. Book promo placements before setting ad dates, because newsletter calendars fill weeks ahead while auction ads start instantly. Request confirmation emails with exact send dates, then build Amazon campaigns to go live three days before the first placement and Facebook tests to run during the placement cluster. That order ensures paid search captures the browsing lift that promo traffic creates, instead of starting cold after the spike fades.
Manage the first week by channel role. Amazon needs daily search-term review: add converting terms as exact matches, exclude irrelevant terms as negatives, and pause keywords spending without clicks after a threshold you set in advance. Facebook needs creative triage: kill the weakest ad after $20–$30 of spend, duplicate the winner into a new audience once, and resist editing everything simultaneously. Promo needs logistics: confirm each placement the day before, verify links the morning of, and screenshot the send for your records.
Reallocate on a fixed rhythm, not on emotion. After seven days, compare each channel's cost per meaningful action — cost per sale for a sales goal, cost per subscriber for list growth, cost per download-day for rank — and shift 10–20% of the remaining budget from the weakest channel to the strongest. Keep at least one promo placement untouched in the schedule, since flat-fee commitments cannot be resized mid-flight. Write the change and the reason in one dated line so next launch inherits the lesson.
Know when to stop a channel entirely. Pause any auction channel whose cost per action exceeds your break-even after 1.5× the normal test spend with no improving trend. Honor promo commitments already paid, but book no new ones into a proven mismatch. Stopping early preserves the budget's second life — cover design, editing, or the next book — which compounds more reliably than forcing a losing channel to work.
Budget sizing and honest expectations
No allocation rescues an unsuitable total. Under $100, pick one channel and one week, and define success as learning your true CPM and conversion rate rather than profit. Between $100 and $500, run the two or three channels the planner suggests but keep creative production cheap — reuse the cover, one tagline, one excerpt graphic — because production costs count against the same wallet. Above $500, reserve 15% of the total for mid-campaign reallocation instead of assigning every dollar on day one; the reserve converts early data into better decisions.
Translate the planner's clicks into money before spending. Multiply expected clicks by your category's plausible conversion rate — 5–15% of ad clicks becoming purchases is a wide but honest planning band for targeted book traffic — then multiply units by royalty per sale. A $500 sales allocation projecting 784 clicks at 10% conversion yields about 78 sales; at $3 royalty that is $234 against $500 of spend, a loss you accept only when series read-through, list value, or rank benefits cover the gap. Run that sentence with your own royalty and conversion figures before approving any budget. The planner deliberately stops at clicks because purchases depend on price, cover, reviews, and series length it cannot see.
Never borrow against rent money for rank. A rank spike spends concentrated dollars for temporary visibility, and the visibility pays only when the book's packaging converts browsers during the spike. When reviews number under twenty, the cover underperforms comps, or the series is incomplete, the same dollars earn more in production quality than in velocity. Advertising amplifies readiness; it does not substitute for it.
Frequently asked depth
Readers often ask whether Amazon or Facebook deserves more money in absolute terms, and the honest answer is that the question has no absolute form. Amazon deserves more when buyers already want the book and need only to find it — launch week for an established series, a price promotion, a category with strong search volume. Facebook deserves more when desire must be manufactured — a debut without reviews, a cross-genre premise, a reader magnet that needs volume. The planner's goal weights encode the average case; your manuscript's awareness level encodes your case. Match the channel to the awareness, not to anyone's success story.
Another recurring question concerns how many promo placements suffice. Count backward from the spike you need: a handful of same-week placements creates a visible rank movement for a narrow category, while a sustained chart presence demands a stack across consecutive days plus auction support. One isolated placement rarely moves durable rank because velocity disperses within hours. Either cluster placements inside a ten-day window or spend the promo share in auction channels instead. The planner's placement count is a budgeting convenience, not a merchandising promise.
Authors also wonder how long to run each channel. Amazon search campaigns can run continuously at maintenance budgets because intent renews daily and negatives accumulate into an asset. Facebook prospecting should run in bounded tests — five to seven days per creative concept — because fatigue erodes performance and refresh costs are real. Promo placements are events with dates, not campaigns with durations; judge each on its own morning plus a three-day tail. Align the planner's monthly-looking shares to these rhythms by converting shares into dated line items before launch.
Attribution confusion deserves a paragraph of its own. Amazon attributes sales to ads generously, Facebook claims view-through influence expansively, and promo newsletters claim the spike exclusively — yet only one wallet funded all three. Expect every dashboard to overclaim its contribution. Judge the push on totals instead: overall units, overall revenue, overall subscribers during the window versus the baseline week before. Channel metrics guide reallocation; business totals judge success.
Finally, authors ask whether the tool replaces professional media buying. It replaces the blank-page problem, not the practitioner. The planner produces a coherent starting split with visible math in seconds, which is exactly what a competent freelancer or a careful DIY author needs as a brief. It does not manage bids, refresh creative, negotiate placements, or interpret anomalies — and it makes no claim to do so. Bring its one-page output to anyone you hire; a good partner will argue with the weights using your history, which is precisely the conversation worth paying for.
Where ongoing tracking lives
Allocations decay without bookkeeping, because memory smooths last month's CPMs into optimism. Keep a simple ledger of planned versus actual spend by channel, alongside the impressions, clicks, and resulting sales or signups each channel produced. The Author Desk at /author-desk exists for that kind of ongoing record: log each push's goal, its starting split, and the week-one costs beside the plan so future budgets inherit evidence instead of hunches. Returning to the same tracking surface every launch turns the planner from a one-time calculator into a compounding habit, where each allocation starts from your own observed rates rather than illustrative defaults.
A closing checklist before you spend
State the goal in one sentence and confirm every enabled channel serves it. Convert the promo dollar row into whole placements with dates, and assign every remainder dollar explicitly. Translate illustrative clicks into break-even sales or subscribers with your own royalty and conversion figures. Schedule ads relative to placement dates, reserve 15% for reallocation, and define the stop rule for each channel in advance. The planner on this page handles the arithmetic of the split; this checklist handles the judgment around it, and books are launched by the combination.