Spine width calculator
Interior pages only — don't count the cover. This has to be an even number: each printed sheet forms 2 pages.
- Text block
- 5.30mm
- Cover
- 0.20mm
This is an estimate from typical paper thickness for each stock, not a measured figure — actual caliper varies by batch. Enter an exact caliper above if you have one, or ask us to confirm it before you finalise cover artwork.
See perfect bound booksHow spine width is worked out
A perfect bound book's spine is the thickness of every text sheet stacked together, plus the cover wrapped around them. Each sheet is printed on both sides, so the text block's thickness is (page count ÷ 2) × the paper's caliper — its thickness per sheet. The cover adds its own caliper on top, plus a thin laminate film if you've chosen one.
Caliper isn't fixed by paper weight (gsm) alone — a gloss, silk and uncoated sheet of the same weight can differ in thickness. The figures this calculator starts with are typical for each stock, not a measured reading from a specific batch, so treat the result as a planning estimate. If you have your paper's exact caliper (from a spec sheet, or your own callipers), use the "I know my paper's exact caliper" option for a precise figure, or ask our team to confirm it before you finalise cover artwork.
Ready to order? RSP prints perfect bound books from 48 to 100 pages, on Gloss, Silk or Laser text stock with a 250–350gsm cover.