Free tools

The arithmetic, done for you

Free, no signup. Both run on the same geometry Pageling uses to generate real print files, so the numbers match what a finished book actually measures.

KDP cover size calculatorSpine width and full wrap dimensions from your trim size, page count and paper. Includes the formula and a reference table.Answers: How wide is my spine? How big is my cover file?
Print resolution checkerDrop in an image and see what it measures at your trim size, and how many pixels 300 DPI actually needs. Measured in your browser.Answers: Is this image sharp enough to print?

More depth in the guides, or let Pageling compute all of it and export the finished files.