Angle Cut Calculator — Miter Saw Angle for Any Corner
Find the exact miter cut to set on your saw so each piece joins at the correct angle. Works for regular polygons (square, hexagon, octagon, etc.) and any custom corner angle — enter the number of sides or the interior corner angle to get the per-board saw setting instantly.
Input method
Set your miter saw to this angle from square (0°) to cut each board
- 1
Interior angle
(4 − 2) × 180° ÷ 4 = 90 - 2
Miter cut per board
180° ÷ 4 = 45Set your miter saw to this angle from square (0°) to cut each piece.
How does this calculator work?
Miter cut = 180°/N for a regular N-sided polygon, or (180° − corner angle) ÷ 2 for any custom corner. A 90° corner → 45° cuts; a hexagon → 30° cuts; a 120° room corner → 30° cuts. Set your saw to that angle and cut both pieces identically.
Formula
How this is calculated
When two boards meet at a corner, each board must be trimmed so that the two cut faces together span the full corner angle. For a symmetrical miter joint (same cut on each piece), each board is cut at half the exterior angle — which equals 90° minus half the interior angle. For a standard picture frame with 90° corners, that gives the familiar 45° miter. For a regular hexagon frame the interior angle is 120°, so each cut is 30° (180°/6).
For a regular polygon with N sides, the interior angle is (N−2)×180°/N and the required miter setting simplifies neatly to 180°/N. For a non-standard corner (a wall that is not exactly 90°, or an odd-angle joint), use the custom-angle mode and enter the actual interior angle measured with a digital angle finder or protractor.
Note that this calculator finds the flat miter cut angle — the horizontal rotation of the saw blade. Crown molding and cove installations also involve a bevel (the tilt of the blade), which depends on the spring angle of the moulding and is a separate calculation. For a flat miter-only cut (baseboards, picture frames, polygon frames), this calculator gives the complete answer.
Frequently asked questions
For a four-sided frame with 90° inside corners, set your miter saw to 45°. This is the result of 180°/4 = 45°, or equivalently 90° − 90°/2 = 45°. Each of the four pieces is cut at 45° on both ends, and when assembled the corners meet flush at 90°.
Use a digital angle finder (bevel gauge with readout), a sliding T-bevel transferred to a protractor, or a phone's angle-measurement app. Place the tool in the corner and note the reading. Enter that angle into the custom-corner mode of this calculator to get the exact cut for each board.
They are the same thing in this calculator. A miter saw angle of 0° makes a perfectly square (straight) cut across the board; 45° tilts the cut 45° from square. The "miter cut per board" value is exactly the number you set on your saw's angle scale. The "cut angle from face" is the complementary angle (90° minus the miter) — the acute angle you would measure if you placed a protractor on the cut end of the board.
TG we-Calculate Editorial Team. (2026). Angle Cut Calculator — Miter Saw Angle for Any Corner [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/angle-cut-calculator
TG we-Calculate Editorial Team. "Angle Cut Calculator — Miter Saw Angle for Any Corner." TG we-Calculate. 2026. https://we-calculate.com/calculator/angle-cut-calculator.
TG we-Calculate Editorial Team, "Angle Cut Calculator — Miter Saw Angle for Any Corner," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/angle-cut-calculator
@misc{wecalculate_angle_cut_calculator, title = {Angle Cut Calculator — Miter Saw Angle for Any Corner}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/angle-cut-calculator}}, year = {2026}, note = {TG we-Calculate} }
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