The direct answer: match the freebie to the book position
A series opener should give away a prequel novella of about 12,000 words. A second or later series book should give away a bonus epilogue with deleted scenes of about 5,000 words. A standalone novel should give away a first-chapters sampler of about 8,000 words. A nonfiction book should give away a checklist or toolkit of about 2,500 words. Place the signup link in the back matter first, on the website second, and with promo partners third. The signup rates in the planner above — 4.5% for a prequel, 3.0% for a bonus pack, 2.5% for a sampler, 5.0% for a toolkit — are illustrative planning assumptions for comparing options, not measured market data. Build time runs about 40 hours for the prequel, 12 for the bonus pack, 8 for the sampler, and 10 for the toolkit, plus roughly 3 hours for formatting and the signup page.
What a reader magnet actually trades
A reader magnet trades one useful file for one email address. The reader finishes a sample, a post, or a book, sees an offer for something extra, types an address, and receives the file in a welcome email. That exchange only works when the free item feels like a continuation of what the reader just enjoyed. A prequel continues a series backward. A bonus epilogue continues it forward. A toolkit continues a nonfiction method into action. The sampler is the weakest trade because it repeats content the reader can already preview without subscribing, which is why its illustrative rate sits lowest at 2.5%.
Your job is to pick the item with the strongest continuation pull for the position your book occupies. Series book 1 needs a backward continuation because new readers have not met anyone yet. Later series books need a forward continuation because readers already know the cast and want more scenes with them. Standalones have no continuation available, so the sampler plus an exclusive extra is the fallback. Nonfiction needs compression, because a busy reader values one usable page more than another chapter.
How the planner math works, step by step
The planner takes three inputs: book position, genre, and current list size. Position and genre select the magnet through a fixed table. List size sets the monthly signup projection. Every rate in the table is an illustrative planning assumption, stated openly so you can compare options without mistaking the output for a forecast.
The selection table works like this. Position series-book-1 with any fiction genre selects the prequel novella. Position series-later selects the bonus epilogue plus deleted scenes. Position standalone selects the first-chapters sampler. Position nonfiction, or genre nonfiction under any position, selects the checklist or toolkit. Nonfiction wins ties on purpose: a teaching book converts better with a usable tool than with a story sample, regardless of series position.
Each magnet carries four fixed numbers. Target length in words: 12,000 for the prequel, 5,000 for the bonus pack, 8,000 for the sampler, 2,500 for the toolkit. Illustrative signup rate: 4.5%, 3.0%, 2.5%, and 5.0% respectively. Build effort in hours: 40, 12, 8, and 10. Placement: back matter plus website plus promo partners for the prequel; back matter plus email-only delivery for the bonus pack; front matter plus website plus retailer preview for the sampler; website plus back matter plus promo for the toolkit.
The signup projection multiplies illustrative reach by the illustrative rate. Reach equals the list size, or 500 when the list is smaller than 500 or zero, because a brand-new author still gets some exposure through promos and retailer pages. So the formula is projected signups per month equals reach times rate. Worked example one: a 1,500-person list with a series opener in romance selects the prequel at 4.5%, and 1,500 times 0.045 equals 67.5, rounded to 68 signups a month. Worked example two: the same 1,500 list with a nonfiction book selects the toolkit at 5.0%, and 1,500 times 0.05 equals exactly 75 signups a month. Worked example three: an 800-person list with a standalone mystery selects the sampler at 2.5%, and 800 times 0.025 equals 20 signups a month, which is why the tool warns that samplers need a second signup point.
The verdict layer reads those numbers and flags two situations. A prequel recommendation against a list under 500 triggers a warning, because 40 hours of writing for roughly two dozen monthly signups pays poorly; the cheaper toolkit-style freebie should come first. A sampler recommendation always triggers a warning, because the lowest tier deserves an explicit fix: add an email-only alternate ending. A zero list triggers an informational verdict that explains the 500-reader floor instead of pretending zero reach produces signups.
Illustrative hypothetical example one: the romance series opener
Consider a hypothetical author, Dana, who is finishing book 1 of a five-book small-town romance series. This example is illustrative and hypothetical, built to show the arithmetic rather than to report anyone's results. Dana has 1,500 subscribers from a co-written anthology. She enters series-book-1, romance, and 1,500. The planner returns the prequel novella: 12,000 words, back matter plus website plus promo partners, 4.5% illustrative rate, 40 hours, 68 projected signups a month.
Dana's decision is whether 40 hours is justified. At 68 signups a month, a year of steady exposure adds about 816 addresses, and each address feeds launch-day buyers for books 2 through 5. She writes the prequel about the couple whose barn wedding closes book 1, ending it on the week the series starts. She places the signup link on the last page of book 1 with the line naming the prequel and the one-field form behind it. She also lists the prequel with two promo partners who feature free series starters. The comparison panel shows her the rejected options: the bonus pack would mismatch because her readers have nobody to miss yet, and the toolkit would mismatch because fiction readers subscribe for story, not worksheets.
Illustrative hypothetical example two: the nonfiction toolkit
Consider a hypothetical author, Marcus, who wrote a standalone productivity book for shift workers. This example is illustrative and hypothetical, with invented numbers for demonstration only. Marcus has the same 1,500 subscribers, mostly from podcast guest spots. He enters nonfiction, nonfiction, and 1,500. The planner returns the checklist toolkit: 2,500 words, website plus back matter plus promo, 5.0% illustrative rate, 10 hours, 75 projected signups a month.
Marcus builds a two-page shift-planning worksheet plus a one-page worked example and a half-page troubleshooting list, totaling about 2,500 words. He spends 6 hours drafting, 2 hours testing the worksheet on three real shift schedules, and 2 hours formatting the PDF. His signup page carries one headline naming the worksheet, three bullets naming the three situations it covers, and one email field. The link sits in the book's back matter right after the chapter that teaches the method, and again on the website beside the podcast episodes. At 10 hours for the highest illustrative tier, the toolkit is the cheapest signup per hour in the whole table, which is exactly why nonfiction wins ties in the selection logic.
One more hypothetical: the standalone mystery sampler done right
Consider a hypothetical author, Priya, with a standalone coastal mystery and 800 subscribers. This example is illustrative and hypothetical. She enters standalone, mystery, and 800. The planner returns the first-chapters sampler at 2.5% with a warning: about 20 signups a month, the lowest tier, because the sampler previews content retailers already show free. The warning tells her the fix, and she follows it. She packages the first three chapters, about 8,000 words, plus an email-only alternate ending of 1,500 words that resolves one subplot differently. The sampler link goes in the front matter, where browsers look before buying, and the alternate ending is mentioned on the signup page as the exclusive part. That exclusive part is what converts a browser into a subscriber; without it she is asking for an email in exchange for nothing new.
Placement: where each link earns its keep
Back matter is the highest-intent location and belongs first for every magnet. The reader just finished the book, trusts the author, and wants more. Put the offer on the final page, name the exact file, and state the delivery: the prequel arrives in the first welcome email. Keep the link on its own lines so tapped fingers on phones hit it cleanly. Test it with a fresh address before publishing, because a dead link on the last page wastes the warmest moment in the funnel.
The website is the second location and the only one the author fully controls. Build one page per magnet with a headline that names the file and the book it extends, three bullets describing what is inside, one email field, and one button. Do not add navigation clutter, additional offers, or long biography text; every extra element lowers the signup rate. Link that page from the site header or footer so podcast listeners and search visitors find it.
Promo partners are the third location and the main source of new reach. Authors with similar audiences feature each other's free items in newsletters and dedicated pages. The prequel and the toolkit travel best here, because a complete small story and a usable worksheet both stand alone for cold readers. The bonus pack travels worst, because deleted scenes assume attachment to characters a stranger has not met; keep the bonus pack email-only and back-matter gated.
Front matter and retailer previews matter mainly for the sampler. The first-chapters file doubles as the retail sample, so upload an overlapping but not identical cut: let retailers show chapter 1 while the signup page offers chapters 1 through 3 plus the exclusive extra. That gap is the reason to subscribe rather than to keep reading the sample.
Genre-specific guidance
Romance readers subscribe for emotional continuation, so the prequel should center the relationship that the series pays off. Write the first meeting, the almost-miss, or the wedding of the background couple. Keep the heat level consistent with book 1 so the magnet pre-qualifies the right buyers. An 800-word bonus scene of domestic aftermath also tests well as a second magnet once the series is complete, because romance audiences collect moments with finished couples.
Thriller readers subscribe for tension and competence, so the prequel should be a compact operation: one mission, one betrayal, one decision that explains the hero's scar or rule. Aim for short chapters and a final-page turn that points directly into book 1's opening. Avoid lore dumps; thriller audiences punish slow freebies by unsubscribing before the welcome sequence ends. The toolkit equivalent for thriller nonfiction crossovers, such as true-crime companions, is a timeline or evidence map rather than a worksheet.
Fantasy readers subscribe for world depth, so the prequel should reveal one place, custom, or magic cost that book 1 only hints at. A map page plus a founding-myth story makes a strong combined magnet, and both fit inside the 12,000-word target. Keep continuity strict: fantasy audiences notice contradictions between a freebie and book 1 faster than any other group, so recheck names, dates, and titles before release. Series-later fantasy does well with in-world documents — letters, decrees, bestiary entries — bundled with the bonus epilogue.
Mystery readers subscribe for puzzles, so the prequel should be a small closed case that shows the detective's method without spending book 1's villain. End with an unsolved thread that book 1 picks up, giving the reader a reason to buy forward. For standalone mysteries, the alternate-ending exclusive works particularly well: one chapter where the detective names a different suspect, clearly labeled as a what-if, gives subscribers something no retailer sample contains.
Sci-fi readers subscribe for ideas and systems, so the prequel should dramatize one technology, first contact, or shipboard crisis that sets the series premise in motion. A two-page ship schematic or system diagram bundled with the story lifts perceived value without adding writing hours. Keep the science consistent with book 1's rules; the audience that fact-checks propulsion will fact-check the freebie.
Nonfiction readers subscribe for compression and usability, across every subject. The toolkit should fit the method onto as few pages as possible: one checklist, one worked example, one troubleshooting list. A memoir-adjacent book, such as a recovery or career-change story, should magnetize the repeatable part — the morning routine, the budget sheet, the scripts for hard conversations — rather than extra chapters of story. Test the worksheet on real users before release, because a tool that fails on first use generates unsubscribes and refund-adjacent resentment toward the book.
Edge cases and failure modes
The most common failure is a magnet that does not match the book's promise. A horror prequel offered in a cozy mystery, a worksheet offered in a romance, or a lore encyclopedia offered before book 1 exists all confuse the reader about what subscribing means. Match the magnet's genre, tone, and heat or violence level to the book exactly, and say plainly on the signup page which book the file extends.
The second failure is asking for the email before delivering value. Signup pages that demand the address before naming the file, or welcome emails that deliver a discount code instead of the promised story, train readers to distrust every later email. Name the file, show its length, and deliver it in the first message. The discount or series pitch belongs in message two or three.
The third failure is the oversized magnet. A 40,000-word prequel that took four months competes with book 2 for writing time and usually converts no better than the 12,000-word version, because subscribers judge the offer by its premise rather than its page count. Stop at the target length in the planner. If scenes remain, save them for the book 2 bonus pack.
The fourth failure is the orphaned magnet: a file with no links pointing at it. A prequel sitting on a hidden page with no back-matter link, no website link, and no promo partners collects nothing regardless of quality. Every magnet needs at least two live entry points before it counts as built. The planner's checklist ends with placement for this reason.
Edge cases deserve direct answers. A box set of a finished series should magnetize the wedding, funeral, or reunion scene the whole arc pointed toward, packaged as a bonus pack, because new box-set readers are mid-attachment by definition. A co-written series should assign the prequel to one pen name's list and share the file, avoiding duplicate magnets that split the audience. A very short book, such as a 30,000-word novella, should use the toolkit or a single bonus scene rather than a 12,000-word prequel, because the magnet should never dwarf the product. An author with no list at all should still build the magnet first and use the 500-reader floor projection, then spend the first promo effort on partner features rather than ads, since partners accept freebies with no audience while ad platforms charge full price for cold traffic.
Deliverability is a quiet failure mode. Welcome emails with large attachments land in spam or clip in Gmail; host the file on the signup platform or a direct download link instead of attaching it. Send a test subscription through a major mailbox provider and a phone mailbox before announcing the magnet, and fix whatever breaks while the audience is still small.
Build workflow and honest hour counts
Budget the hours before writing. The sampler takes about 8 hours because the chapters already exist: 2 hours selecting and cleaning the cut, 2 hours writing the exclusive extra, 2 hours formatting, 2 hours building and testing the page. The toolkit takes about 10 hours: 5 drafting, 2 testing on real inputs, 3 formatting and page setup. The bonus pack takes about 12 hours: 7 writing the epilogue and assembling deleted scenes, 2 editing, 3 formatting and page setup. The prequel takes about 40 hours: roughly 28 writing 12,000 words at a sustainable pace, 5 revising, 4 formatting across PDF and EPUB, and 3 building and testing the signup page. These are working estimates for planning, not quotes; a fast drafter with an existing template finishes sooner, and a perfectionist formatting for print finishes later.
Sequence the work in the checklist order the tool shows. Draft first, because everything else depends on the file existing. Edit second, with one revision pass aimed at tone match rather than exhaustive polish; the magnet should read like the book, not better than it. Format third, exporting both PDF and EPUB so phone readers and desktop readers each get a file that opens. Build the signup page fourth, with the single headline, three bullets, one field, and one button described earlier. Place the links fifth, in back matter and on the site, then claim each one with a test address and read the welcome email like a stranger.
Measuring the signup rate and tracking it on Author Desk
A rate only means something against the tool's assumption. Record the file offered, the page shown, and the resulting addresses each month, then divide addresses by page visitors to get the observed rate. If the observed rate trails the illustrative tier by half or more for two consecutive months, change one variable: the headline, the cover thumbnail, or the placement, never all three at once. Small lists need longer windows before judging; under 200 monthly visitors, wait a full quarter rather than reacting to one thin month.
Keep these numbers where the rest of the launch figures live. Author Desk at /author-desk is the place to track the magnet totals alongside list growth and launch revenue, so the signup count, the observed rate, and the hours spent stay visible when planning the next book. Review the magnet line each month when the newsletter figures go in, and retire or replace any file whose observed rate stays below its tier after two placement fixes. A magnet is infrastructure, and infrastructure earns its review slot.
Frequently asked depth
Readers deciding on a magnet usually circle the same six doubts, answered here with the working detail behind the tool's short labels.
A freebie earns the address when it continues the book. Ask of every candidate file whether a reader who just finished the sample would describe it as more of what they liked. Prequels, epilogues, and toolkits pass that test; generic wallpapers, playlists, and author interviews usually fail it, because they decorate rather than continue.
Series openers carry the prequel because discovery happens at book 1. Most new readers meet an author through the first book's sample, cover, or ad, so the magnet attached to that entry point compounds across the whole series. Writing the prequel before book 2 launches gives every later promo a free entry point to feature.
Later books carry the bonus pack because attachment deepens with pages read. By book 2 the reader knows the cast, so extra scenes with beloved characters out-pull another origin story. Deleted scenes cost little, since the material already exists in cut files, and the new epilogue gives the package a spine.
Teaching books carry the toolkit because implementation is the reader's bottleneck. A method understood but not applied creates no loyalty; a worksheet completed creates a small win the reader credits to the author. That credit is what the email relationship runs on afterward.
Link location decides roughly half the outcome. Back matter converts finished readers, the website converts referred visitors, and promo partners supply cold readers at volume. A magnet with all three entry points can outperform a better file with one, which is why the placement checklist item is mandatory rather than advisory.
Build time should follow list size. Under 500 subscribers, ship the 8-to-10-hour options first and let their signups fund the 40-hour prequel in attention terms. Past a few thousand subscribers, the prequel's higher tier and series-long compounding justify the writing weeks. The planner's warning at small lists exists to enforce exactly this sequencing.