--- title: "KDP sudoku interior specs: trims, margins and solutions | Once Books" description: "The trim sizes, margins, gutter, bleed and solutions layout a KDP sudoku interior needs to pass review, with the large-print grid numbers that sell." source: "https://www.oncebooks.com/blog/kdp-sudoku-interior-specs" --- 1. [Home](https://www.oncebooks.com/) 2. [Blog](https://www.oncebooks.com/blog) 3. KDP sudoku interior specs: trims, margins and solutions Blog # KDP sudoku interior specs: trims, margins and solutions [The Once Books team](https://www.oncebooks.com/authors/team) · 3 October 2026 · 6 min read - [kdp](https://www.oncebooks.com/blog/tag/kdp) - [sudoku](https://www.oncebooks.com/blog/tag/sudoku) - [print](https://www.oncebooks.com/blog/tag/print) Most first sudoku books that fail KDP review fail on the interior, not the puzzles. The grids are fine; the page geometry is wrong, or the boards were shrunk to pack more onto a sheet. Getting the trim, margins, grid size and resolution right the first time is mostly a matter of knowing the numbers, so here's the set that matters most in this niche. KDP updates its guidance from time to time, so treat these as the working numbers and check the current KDP help pages before a big run. ## Trim size The [trim size](https://www.oncebooks.com/glossary#kdp-trim-size) is the finished page dimension. For sudoku, the deciding factor is how writable the grid stays, because a solver pencils candidate numbers into cells and needs the room. - **8.5 by 11 inches**: the default for large-print sudoku. One roomy 9 by 9 grid per page with space to spare. - **8 by 10 inches**: slightly more compact, still very comfortable, a little cheaper to print. - **6 by 9 inches**: fine for a compact or travel book, but the cells get small. Not the first choice for a large-print title. Pick one trim and design the whole interior to it. The studio exports any KDP trim from the same project, so you can produce a large-print and a standard edition from one generation. ## Grid size and puzzles per page This is the spec people get wrong to save paper, and it's the fastest way to a one-star review. A sudoku cell has to hold more than a single digit: a careful solver writes two or three small candidate numbers into an empty cell, so cramped grids fight the way the puzzle is actually played. For large print, put one 9 by 9 grid on a page with a generous outer margin. Two grids to a sheet halves your cell size and doubles the eye strain, which is the opposite of what a large-print buyer paid for. If you want more puzzles per book, add pages, don't shrink grids. ## Margins Margins are the white space between your content and the page edge. Puzzles want more breathing room than dense text does. - **Outside, top and bottom**: at least 0.25 inch. For a grid, 0.5 inch reads better and keeps the board clear of the trim. - **Inside (the gutter)**: the margin nearest the spine, and it must grow with page count so the binding doesn't swallow the grid. ## Gutter by page count The [gutter margin](https://www.oncebooks.com/glossary#gutter-margin) is the single spec most often set too small. A thick book needs a wider inside margin because more pages curve into the spine. As a working guide: - Up to 150 pages: about 0.375 inch - 151 to 300 pages: about 0.5 inch - 301 to 500 pages: about 0.625 inch - 501 to 700 pages: about 0.75 inch A generated interior sizes the gutter for your page count automatically, so you don't redo the layout every time the book grows. ## Bleed [Bleed](https://www.oncebooks.com/glossary#bleed) is the small overrun (0.125 inch) past the trim that lets colour or art print right to the edge after cutting. A plain sudoku interior with white margins needs no bleed. Add it only if a page carries a full-bleed background or a border that touches the edge, and then extend that art 0.125 inch past the trim on every outside side. Don't add bleed "just in case". If your content doesn't reach the page edge, a bleed setting only shifts your safe area and can trip a review warning. No edge art means no bleed. ## The solutions section Every board needs its answer, and a book of unsolvable puzzles gets returned. Sudoku solutions are compact, so they don't go one-per-page like the puzzles. They belong in a numbered solutions section at the back, several small grids to a page, in the same order as the puzzles. Two things make the section usable. Number each solution to match its puzzle, and confirm each printed answer is the single correct one for that grid. Every board in the studio is verified by a solver to have exactly one solution before it reaches a page, so the answer at the back is the only answer, not one of several. ## Resolution and the file itself - **300 DPI**: the print standard. The grid lines and the printed digits must render crisply at the finished size, not just on screen. - **A [print-ready](https://www.oncebooks.com/glossary#print-ready) PDF**: fonts embedded, one page per book page, at the exact trim (plus bleed only if used). - **Black and white**: sudoku interiors are almost always black-and-white, which prints far cheaper per page than colour and reads perfectly. The [KDP sudoku maker](https://www.oncebooks.com/kdp-sudoku-maker) exports a print-ready 300 DPI [interior PDF](https://www.oncebooks.com/glossary#interior-pdf) with these margins and gutter already applied, and builds the numbered solutions section to match. If you want to see the output before committing, the [free sudoku generator](https://www.oncebooks.com/tools/sudoku-generator) prints a single board and its solution at a large-print size. ## The short checklist Before you upload: one trim throughout, one roomy grid per page for large print, at least a 0.25 inch outside margin, a gutter sized to your page count, bleed only if art reaches the edge, 300 DPI, and a numbered solution for every puzzle. Get those right and the interior clears review. For the rest of the path, from picking a level to setting up the listing, see the full guide to [making and selling sudoku books on KDP](https://www.oncebooks.com/blog/how-to-make-and-sell-sudoku-books-on-kdp). The margin and gutter maths carry straight over from the [word search interior specs](https://www.oncebooks.com/blog/kdp-word-search-interior-specs) if you publish both. ## Try the tool Free, in your browser, no sign-up. Make one, then build the whole book in the studio. [Sudoku generator Pick a difficulty and print a sudoku plus its solution. No watermark. Try it free](https://www.oncebooks.com/tools/sudoku-generator) ## Questions parents ask **What size should a KDP sudoku book be?** For large print, 8.5 by 11 inches is the most common and buyer-friendly trim, with 8 by 10 a close second. A single 9 by 9 grid needs room to stay writable, so smaller trims like 6 by 9 get tight, especially for seniors. **How big should a sudoku grid be on the page?** Big enough to pencil two or three candidate numbers into a cell without crowding. On a large-print 8.5 by 11 page, one grid per page with a wide outer margin reads far better than two grids squeezed onto a sheet. **Where do the solutions go in a sudoku book?** In a numbered solutions section at the back, in the same order as the puzzles, several small grids to a page. A reader checks any board in seconds, and every solution is the one and only answer for that grid. ## Related reading - [KDP spine width and cover size: the exact formula](https://www.oncebooks.com/blog/kdp-cover-size-and-spine-width) — How to calculate KDP spine width and full-wrap cover size: the per-page paper multipliers, the bleed maths, three worked examples and the common mistakes. - [How we make sure every sudoku has one solution](https://www.oncebooks.com/blog/how-we-guarantee-one-solution-sudoku) — How our sudoku generator works: fill a grid, remove clues in pairs, and re-solve after every removal so each board has one answer. Real code and timings. - [How to publish a paperback on KDP: the checklist](https://www.oncebooks.com/blog/kdp-paperback-publishing-checklist) — The ordered checklist for publishing a paperback on Amazon KDP: trim, paper, page count, interior and cover PDFs, metadata, pricing, proof and review. ## Keep reading - [Answers](https://www.oncebooks.com/answers) — One sharply-scoped question per page, cost, safety, timing, printing, answered in a couple of sentences before the detail. - [Glossary](https://www.oncebooks.com/glossary) — Plain definitions of the vocabulary: the Character Sheet, the Consistency Engine, style profiles, drift. - [Help centre](https://www.oncebooks.com/help) — Task-shaped instructions for making, printing and sharing a book once you have started one. [← All posts](https://www.oncebooks.com/blog) Try this tool [Sudoku generator Pick a difficulty and print a sudoku plus its solution. No watermark. Try it free](https://www.oncebooks.com/tools/sudoku-generator)