Cover spread size calculator

The number you really need is the whole spread

A full cover is not just “front cover width × 2.” The spine sits between the covers, and bleed extends the artwork beyond the trim. This calculator adds those pieces so you can compare one finished spread size with the printer’s template.

Spine width is the moving part

Page count matters, but paper thickness and binding method matter too. Treat an estimated spine as a layout placeholder; use the printer’s confirmed spine width for the final file.

Three checks before you export

• Use the printer’s bleed value, not a remembered default.
• Make sure front/back placement matches the binding direction.
• Do not turn a rough spine estimate into the final production value.

A5 example

For an A5 book, the basic spread width is 148 mm × 2 + spine + left/right bleed. The height is 210 mm plus top/bottom bleed.