KerfCalc – Woodworking Math

Every calculation stays exact — type 1-3/4 the way you'd say it. No ads, no accounts, no subscription. Works with no signal, in the shed.

KerfCalc is a set of woodworking calculators for the weekend workshop. Clean, fast, and built for the way woodworkers actually measure: in fractions.

No ads. No accounts. No subscription. Works with no signal at all.

BUILT FOR FRACTIONS

Type 1-3/4 the way you'd say it. A custom keypad puts the fraction keys where your thumb already is, with shortcuts for the sixteenths and eighths you use constantly. Every calculation stays exact — no decimal drift, no 0.749999 where 3/4 belongs.

Switch the whole app to millimetres whenever you want, and it remembers.

FREE TOOLS

• Converter — fractions, decimals and millimetres, three ways • Board feet — with a running tally and a cost estimate at your price per board foot • Shelf spacing — even divider positions, marked from one end so errors can't accumulate • Screws & pilot holes — the pilot and countersink size for every screw gauge, by wood hardness

UNLOCK EVERYTHING — ONE PAYMENT

• Cut list optimizer — for boards and for sheet goods. Counts the blade. • Saved cut lists — name a job and come back to it • Board inventory — what's actually in your rack, with total board feet • Stain & finish — how much to buy, coats and waste buffer included • Joinery reference — dovetail slopes with angles, box joints, proportion rules • Golden ratio — harmonious proportions from a single dimension

IT COUNTS THE KERF

Four 24-inch pieces from a 96-inch board sounds like it fits. It doesn't — three cuts at 1/8" each eat 3/8", and the fourth piece comes up short. KerfCalc plans around the blade, for boards and for full sheets, and shows you the layout.

IT KNOWS A 2x4 ISN'T 2x4

Tap a nominal size and you get the real one: 1-1/2 x 3-1/2. Getting that wrong is the fastest way to build a carcass an inch off.

HONEST NUMBERS

When a value can't be marked on a tape, KerfCalc says so rather than pretending. When there are two right answers —what the lumberyard charges versus what you can actually cut — it gives you both.

Everything stays on your device. Nothing is collected, and nothing is sent anywhere.