Free tool
Spine width calculator.
Enter your page count and paper to get the spine width in mm and inches — plus the full cover-wrap size with bleed, and a warning if the spine is too thin for text.
19.6 mm spine
Full cover wrap (W × H, incl. bleed)329.9 × 235.3 mm
Formula308 × 0.0025″/page
Wide enough for spine text (title + author). Keep a 1.6 mm safety margin from each fold.
Based on Amazon KDP paper specs. IngramSpark and other printers differ slightly — if you print on both, design to the narrower spine and keep spine text centred. Page counts round up to the nearest even number. Hardcover (case wrap) adds board thickness and a larger bleed — always confirm with your printer’s template.
These help you plan. We make the real files.
When it’s time to build the interior, the spine and a print-ready cover, we prepare them precisely to your printer’s spec — with a fixed quote and a delivery date.
Want an exact spine and page count? Send us your manuscript for a fixed quote.