Caliper is the critical input
Two papers with the same basis weight can have different thickness. Use the printer’s measured stock caliper or a verified paper specification for the actual job.
SPINE / BOOK BLOCK
Turn page count into
a measured thickness model.
Estimate the physical book block from leaves and real paper caliper rather than guessing a spine from page count alone. Keep binding and cover-design allowances visible as separate inputs.
✓ Formula shown✓ Editable assumptions✓ Browser-local
Model thickness from leaves and caliper
leaves = interior pages ÷ 2
modeled book-block thickness = leaves × paper caliper + binding/compression allowance
Approximate book-block spine
Leaves–page count ÷ 2
Book block–mm
Design span–spine + entered hinge allowance
MODEL
Use measured or provider caliper.
Coating, compression, adhesive, grain and binding process can change the finished spine.
Page count alone cannot produce a trustworthy spine width.
Binding changes compression
Perfect binding, case binding and other processes can add adhesive or compress the book block differently. The allowance field lets the provider’s empirical correction remain explicit.
Cover design needs more than spine
Hinge, wrap, bleed and board turn-ins are separate design dimensions. The optional hinge allowance is reported independently so it is not confused with the physical book-block thickness.