Angle Cut Calculator

Find the saw angle to cut each board so two pieces meet at a given joint angle.

How the Math Works

The Angle Cut Calculator uses the formula miter = (180 − joint angle) ÷ 2 to determine the precise angle at which to cut each board so they meet perfectly at a corner. This works because when two boards form a joint, the sum of their miter cut angles must equal the supplement of the joint angle (180° minus the joint angle). Dividing this value by two gives the identical cut angle for each board, ensuring they fit together seamlessly without gaps or overlaps.

Practical Applications

To use this calculator, first measure the angle where the two boards will meet using a protractor or angle finder. Enter this joint angle into the calculator, which outputs the required miter cut angle. Set your miter saw or protractor to this calculated angle and cut both boards identically. This method is essential for projects like picture frames, crown molding, or custom furniture, where precise corner joints are critical for structural integrity and aesthetic appeal.

Day-to-Day Use

This tool simplifies DIY projects by eliminating guesswork and reducing material waste. Whether you're installing baseboards, building a birdhouse, or crafting a picture frame, accurate miter cuts ensure professional results without visible gaps or misaligned seams. It empowers homeowners and crafters to achieve clean, precise finishes using common tools, saving time and frustration while enhancing the quality of their work.

Worked example

90° corner → 45° per board.

FAQ