Creative Tools
Book Cover Dimensions Calculator
Enter trim width/height, spine, bleed and wrap to see full cover flat width and height.
What size is a full book cover flat?
A full paperback cover flat is wider than a single trim page: you need back cover + spine + front cover, plus bleed on the outer edges and any wrap or flap. Flat width = wrap + bleed + trim width + spine + trim width + bleed + wrap; height = bleed + trim height + bleed (extend if your template adds vertical wrap). Get spine from page count and paper bulk first — see the spine width calculator — then assemble the flat here. Printers supply templates; this tool is a planning check before you build artwork. For pixel crops and ratios elsewhere in creative work, aspect ratio helps keep mockups consistent.
Worked example
Trim 152 × 229 mm, spine 15 mm, bleed 3 mm, no wrap → width = 3+152+15+152+3 = 325 mm; height = 3+229+3 = 235 mm.
Limits and assumptions
Does not add hinge gaps or barcode boxes. Always match the printer’s PDF template for safety margins and spine text safe area.
Frequently asked questions
Is bleed on both sides of the spine?
Bleed sits on the outer edges of the flat, not between panels and spine — follow your template’s guides.
What about dust jackets?
Enter flap wrap on each side; height rules may differ — confirm with the jacket template.
Units?
Use the site unit toggle; enter all dimensions in the same system.
Why is my printer’s flat wider?
Extra spine hinge, boards or larger bleed requirements — trust their template over a generic estimate.