The calculation
paper thickness = leaves × single-sheet caliper
paper mass = leaves × page area in m² × GSM
Worked example
A 200-page block contains 100 leaves. At 0.10 mm per leaf, it is 10 mm thick before binding effects. With 148 × 210 mm pages and 80 GSM paper, the theoretical paper mass is 248.64 g.
Paper-only dimensions
The thickness estimate is for the stack of paper at the measured caliper. Sewing swell, folds, adhesive, compression, endpapers and cover boards are excluded. It is not a final cover-spine dimension. For a case or dust jacket, measure the assembled and pressed book block using the binder’s production method.
GSM is not caliper
Grammage describes mass per area. Caliper describes thickness. Papers with the same GSM can have different bulk, coating and compression behavior. Enter a measured thickness or a supplier’s caliper value instead of relying on a universal GSM-to-thickness conversion.
The mass estimate uses finished leaf dimensions and ignores trimming waste. If you are estimating purchased sheets, use their untrimmed size and sheet count separately. Add covers and packaging separately when planning the final parcel.
Common questions
Why divide pages by two?
A leaf has two page faces. Counting each face as a separate physical sheet would double both thickness and mass.
Will this tell me the finished spine width?
No. It estimates paper thickness only. Measure the bound block before final cover production.