Free tool
KDP spine width & cover size calculator
Enter your trim size, page count and paper to get the exact full-wrap paperback cover size Amazon KDP expects.
Spine width
0.450 in
Full cover width
12.700 in
Full cover height
9.250 in
Includes 0.125 in bleed on every outside edge. In pixels at 300 DPI: 3810 × 2775. Keep spine text at least 0.0625 in from each spine edge.
How the math works
Full cover width = back cover + spine + front cover + bleed on both sides. Spine width is your page count multiplied by the paper's thickness per page. These are estimates based on KDP's published figures; always confirm with KDP's cover template before you upload.
Want your finished cover checked automatically? Manucheck's Cover Analyzer checks dimensions, bleed and spine text against KDP's rules.
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