Enter your page count, paper stock, and trim size. SpineGen calculates the spine and builds a print-ready wraparound cover — back cover, spine, front cover — with bleed, fold lines, and safe zones marked.
Every paper stock has a PPI — pages per inch. A 400-page book on 400 PPI paper has a 1-inch spine. Thicker, uncoated papers have lower PPI (fatter spine); thin coated gloss has higher PPI (skinnier spine). Same page count, different paper, different spine.
Printers count pages the way a book does: each side of a sheet is one page. If your manuscript PDF has 200 pages, that's 100 physical sheets. SpineGen expects the page count — the number your PDF viewer shows.
A perfect-bound cover prints as a single flat piece: back cover + spine + front cover, plus bleed on all four sides. Design it as one canvas so artwork can run continuously across the spine — then the printer trims and folds.
Under about 0.25 in, spine text gets risky — a tiny binding shift makes it wrap onto a cover. Under roughly 24 pages, perfect binding isn't practical at all; that's saddle-stitch (stapled) territory, where there's no printed spine and your page count must divide by 4.
SpineGen is free to use. If it saved you a proof round (or an angry email from pre-press), you can buy me a coffee.
☕ Buy me a coffeeOne-time $4.99 gets you this template as a layered SVG and a true-vector PDF — guides on a separate layer, ready for InDesign, Illustrator, Affinity, or Canva.
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