KDP trim size recommender
Free KDP cover size calculator
Recalculate the full wrap when KDP flags your cover size.
A cover that looked fine in the preview can still be sized from the wrong page count. Rebuild the spine, bleed, and wrap from your final page count, trim, and paper type before you place cover art.
Checked:
✓Full wrap from your final page count✓Spine, bleed, and 300 DPI Canva pixels✓Downloadable SVG guide with bleed lines
Paperback cover dimensions
Spine width0.450 in11.44 mm
Full cover size12.700 × 9.250 in322.59 × 234.95 mm
Canvas (300 DPI · Canva)3810 × 2775 px300 DPI · Canva custom size
Spine text
Eligible: more than 79 pages. Keep at least 0.0625 in from each spine edge.
Paperback calculation uses KDP's published 0.125 in bleed and current paper thickness factors. Always confirm the final page count after interior formatting.
Why the final page count controls your cover
The spine is calculated from the page count after the interior is formatted. A cover built from a draft page count can shift the front and back panels even when the artwork itself looks polished.
Every paperback cover also needs 0.125 inches of bleed on the top, bottom, and outside edges. The calculator includes that bleed in the full file size.
- Recalculate after every interior pagination change
- Do not place spine text below 80 pages
- Keep important text away from trim and fold lines
Setting up your cover in Canva without rejections
Most authors design their book covers in Canva. To avoid KDP size mismatches, create a new design using Custom Size with the exact pixel dimensions displayed above (at 300 DPI), which already factor in the 0.125-inch trim bleed.
Keep all live text, barcodes, and essential artwork at least 0.25 inches inside the outer edge (the safe margin). When finished, export from Canva as 'PDF Print' with 'Crop marks and bleed' unchecked unless you intentionally aligned bleed lines.
- Copy the 300 DPI canvas pixels directly into Canva Custom Size
- Account for spine width changes if interior page count shifts by even 2 pages
- Export as PDF Print for press-ready 300 DPI resolution
Use the guide without creating a rejection
Download the SVG as a design guide, place it in your design file, and keep it on a non-printing layer. Export one continuous PDF containing back cover, spine, and front cover.
This calculator covers paperback geometry. Hardcover case wrap and dust jacket measurements use different rules.
Error code to fix: wrong cover size or spine
Many technical cover rejections are geometry problems, while artwork and content issues are separate. Recalculate from the formatted page count, then export one continuous wrap.
| Error or symptom | Likely cause | Next check | Fix in the source file | Re-test |
|---|---|---|---|---|
| Cover size / wrap dimensions do not match | The wrap was built from a draft page count, so the spine and panel widths are wrong. | Recount the final formatted pages and recompute the wrap width for the trim and paper. | Rebuild the full wrap from the final page count, the chosen trim, the paper type, and 0.125 in bleed. | Compare the new wrap against the official cover calculator before uploading. |
| Spine text missing, clipped, or overflowing | The book has 79 pages or fewer, or text sits too close to the spine edge or outside the panel. | Confirm the page count is above 79 and measure text distance from each spine edge. | KDP prints spine text only when the book has more than 79 pages. Keep 0.0625 in from each spine edge and stay inside the spine panel. | Review the spine panel in the cover preview, then upload the corrected wrap. |
| Bleed or trim mismatch on the cover | Bleed was not added on the outside edges, or it was wrongly added to the spine-facing edges. | Measure the outside edges for the missing 0.125 in of bleed. | Add 0.125 in bleed on the top, bottom, and outside edges. Spine-facing edges do not receive extra outside bleed. | Recheck the bleed on all four outside edges, then re-upload. |
| Artwork shifted after a pagination change | The interior page count changed after the cover was built, moving the spine position. | Recount the interior and note where the spine now falls. | Recalculate the wrap after every interior page-count change. Do not reuse a cover built from a draft pagination. | Recompute and re-export the wrap, then confirm the spine matches the final interior. |
Calculation examples from the ShipMyBook cover engine
Each row below is generated live by ShipMyBook's production formula — final page count × paper factor (white 0.002252 in, cream 0.0025 in, premium color 0.002347 in, standard color 0.002252 in), plus 0.125 in bleed on every outer edge. The engine accepts numeric inputs from 24 to 828 pages, but KDP's valid range depends on trim, ink, and paper; these examples use supported combinations. No number is copied from a static table.
These are ShipMyBook calculation examples, not Amazon template output. Always compare the final numbers against KDP's official cover calculator before you upload.
| Trim, pages, and paper | Spine | Full wrap (W × H) | 300 DPI canvas (px) | Spine text |
|---|---|---|---|---|
| 6 × 9 in, 100 pages, white paper | 0.225 in | 12.475 × 9.250 in | 3743 × 2775 px | Allowed |
| 6 × 9 in, 79 pages, white paper | 0.178 in | 12.428 × 9.250 in | 3728 × 2775 px | Not allowed (fewer than 80 pages) |
| 6 × 9 in, 80 pages, white paper | 0.180 in | 12.430 × 9.250 in | 3729 × 2775 px | Allowed |
| 5.5 × 8.5 in, 200 pages, cream paper | 0.500 in | 11.750 × 8.750 in | 3525 × 2625 px | Allowed |
| 5 × 8 in, 300 pages, white paper | 0.676 in | 10.926 × 8.250 in | 3278 × 2475 px | Allowed |
| 6 × 9 in, 400 pages, premium color | 0.939 in | 13.189 × 9.250 in | 3957 × 2775 px | Allowed |
| 8.5 × 11 in, 600 pages, standard color | 1.351 in | 18.601 × 11.250 in | 5580 × 3375 px | Allowed |
| 5.5 × 8.5 in, 24 pages, white paper | 0.054 in | 11.304 × 8.750 in | 3391 × 2625 px | Not allowed (fewer than 80 pages) |
| 6 × 9 in, 150 pages, cream paper | 0.375 in | 12.625 × 9.250 in | 3788 × 2775 px | Allowed |
| 6 × 9 in, 250 pages, standard color | 0.563 in | 12.813 × 9.250 in | 3844 × 2775 px | Allowed |
FAQ
Frequently asked questions
How do I create a KDP cover in Canva?
Use the 300 DPI pixel dimensions from this calculator. In Canva, click 'Create a design' then 'Custom size', switch units to px, enter the width and height, and paste your design. Export as PDF Print at 300 DPI.
How is the KDP paperback spine width calculated?
The calculator multiplies your final page count by the paper-specific factor, the same way KDP's cover calculator does. Confirm the result against KDP's own calculator before uploading.
How much bleed does a KDP cover need?
KDP requires 0.125 inches on the top, bottom, and each outside edge. The spine-facing edges do not receive an extra outside bleed.
Can I put text on a 79-page spine?
No. KDP prints spine text only when a book has more than 79 pages, so the practical minimum is 80 pages.
KDP says my cover size is wrong. What do I recalculate?
Recalculate the full wrap from the final formatted page count, trim, paper, and 0.125 in bleed. Do not use a draft page count. Spine text needs more than 79 pages.
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Get the wrap size before you pay for files.
Calculate the wrap from your final page count, paper type, and trim size. Download a free guide, then check the interior and cover together before upload.