JOIXTSHRINKULATOR
joixt
Sign in

Shrinkulator

Estimate how much a board will shrink or swell between two moisture contents. The math is from the USDA Forest Products Lab Wood Handbook (FPL-GTR-190): wood doesn't move above ~30% MC, and below that, dimensional change is linear with MC.

Final width: 11.716"

Change: -0.284" (-2.37%)

Board shrinks as it loses moisture.

The formula
ΔL = L0 × (Stotal / 30) × (MC0 − MC1), where Stotal is the species' total tangential or radial shrinkage from green to oven-dry. Both moisture contents are clamped to 30% for the calculation.
SAVE THIS SHRINKULATOR CALCULATION

Joixt is the shop companion: cut-list optimizer, project pricing & branded quote PDFs, lumber inventory, and the same calculators as this page — synced between your phone and your shop computer.

Sign up — freeAll tools