How paperback wrap sizing works
A full cover runs from back to spine to front. For an ordinary left-to-right paperback, full width = outside bleed + back trim width + spine width + front trim width + outside bleed. Full height = top bleed + trim height + bottom bleed. The two fold lines are bleed + trim width and bleed + trim width + spine width from the left file edge. The calculator treats these as straight geometric layout measurements, not binding-machine instructions.
Example: 200 final pages, KDP black-and-white white paper, 6 × 9 in trim, and 0.125 in bleed give a 0.4504 in spine, 12.7004 × 9.25 in full cover, and folds at 6.125 and 6.5754 in. At 300 ppi the unrounded width needs at least 3,811 pixels. Pixel dimensions help size art but do not replace a PDF with the correct physical page box.
Spine width: per page or per sheet?
KDP’s paperback cover guide publishes per-page spine multipliers in inches: 0.002252 for black-and-white white, 0.0025 for cream, 0.002347 for premium color, and 0.002252 for standard color. Multiply by the final interior page count; do not divide it by two in KDP mode. These are KDP paperback assumptions, not universal paper properties.
If your supplier gives the caliper of one two-sided physical sheet, an estimate is ceil(pages ÷ 2) × sheet caliper. Paper compression, adhesive, binding method, added blanks, and cover stock can alter the finished spine. A printer-supplied exact spine width or official generated template should take precedence over this estimate. Hardcovers, dust jackets, flaps, hinges, and right-to-left wraps need different layout.
Bleed, type safety, and proofing
KDP requires 0.125 in bleed on the outer left/right and top/bottom edges of a paperback cover, at least 0.125 in for front/back text inside trim, and 0.0625 in of spine-text space on each fold side. KDP does not allow spine text on paperback books of 79 pages or fewer. These values and eligibility should be checked against KDP’s current cover guidance when preparing a KDP job.
IngramSpark’s cover guidance has its own template, barcode, bleed, and type-safety rules. The generic layout here does not generate IngramSpark- or Lulu-compliant upload art. Export the reference measurements, then work in the printer’s own template and confirm the proof or preview. Do not place a barcode using this calculator’s safe rectangle alone.
Frequently asked questions
Does a 200-page book contain 200 sheets?
No. A two-sided physical sheet usually carries two page faces. The sheet-caliper mode estimates 100 physical leaves for 200 pages; KDP’s published coefficients are per page and already account for its stock calculation.
Why did the spine change after exporting my interior?
The final PDF may contain additional pages or blanks. Use the actual final page count and the publisher’s paper choice before finalizing the cover; even a few pages shift the folds.
Is the downloadable SVG upload-ready?
No. It is a dimensional guide with safety and fold lines, not your finished artwork or a publisher template. It does not add a barcode, CMYK color profile, PDF page boxes, fonts, or production tolerances.
Can I use it for a hardcover or a right-to-left book?
No. This page plans an ordinary paperback back–spine–front wrap. Hardcovers may need hinge and wrap allowance, and right-to-left cover panel order is reversed. Use the relevant official template.