Angles for dummies — no trig required

Cut it right.The first time.

Stairs, rafters, crown molding, any triangle on the job. You type the numbers you actually have. We hand you the cut angle and tell you in plain English what to set your saw to.

Stair Stringer rise & run → cut angle

Total Rise — floor to floor, top of finished surfaces

Target Step Rise — comfortable is 7–7¾"

Tread Run (depth) — typical 10–11"

Roof Rafter pitch & span → every cut

Enter slope as

Pitch — rise in 12

Building Span — outside wall to outside wall

Ridge Board Thickness — deducted from run

Crown Molding compound miter & bevel

Spring Angle — stamped on the molding; usually 38° or 45°

Wall Corner Angle — 90° for a square corner; measure it if unsure

Triangle Solver any right triangle, two knowns

What do you know?

Rise (vertical leg)

Run (horizontal leg)

Free on the web. Built for the truck.

Every calculator here is free, forever, in your browser. The app is for when the job site has no signal.

Web

All calculators, full access
Imperial & metric toggle
Works in any phone browser
Nothing to install

App iOS + Android

Paid

Works fully offline — no signal needed
Save & name your projects
No ads, ever
Everything on the web version