Construction Calculator - Site Measurement

Miter Angle Calculator

Calculate the basic miter cut angle from a corner angle.

Reviewed: August 26, 2026

Calculate Miter Angle

For the Miter Angle Calculator, enter corner angle. It halves the entered corner angle for two equal mating cuts and reports the complementary saw-setting reference.

Construction measuring tools arranged beside a residential building project

Formula and input notes

Equal-piece miter cut = included corner angle ÷ 2

InputPractical note
Corner angleEnter the included angle between the two finished pieces. The equal-miter result assigns half of it to each cut.
Miter Angle Calculator measurement plan showing Corner angle degrees

Worked miter angle example

Miter Angle Calculator example: For two equal pieces meeting at 90°, each miter is 90° ÷ 2 = 45°. The complementary saw reference is 45°.

What the converted result represents

Use the miter and complement as layout references, then test the setup on scrap before cutting finish stock.

Limits of the geometric model

Out-of-square corners, unequal member directions, spring angles on molding, saw gauge conventions, and compound cuts require additional geometry.

Questions specific to this calculation

When is half the corner angle the correct miter setting?

Enter the included corner angle between two equal pieces; the calculator divides it in half for a symmetric miter joint.