Baseboard
Baseboard Miter Calculator
Flat against the wall — no bevel. Set this miter angle on the saw from the square detent.
Quick answer
A square 90° corner cuts at 45° per piece. For any other corner, the saw setting is 90 minus half the corner angle — so a 92° corner is 44°, an 88° corner is 46°.
Measure the corner — don't trust 45°
The single biggest cause of gapping baseboard is assuming every corner is a perfect 90°. They almost never are. Drop a digital angle finder into the corner, read the actual angle, and feed it into the calculator. A 2° error at the corner is a visible wedge of light at the top of the joint. For outside corners, hold a scrap on each wall and measure where they cross.
FAQ
+What angle do I cut baseboard corners?
For a standard 90° corner, cut each piece at 45°. If the corner is off — say 88° or 92° — set the saw to 90 minus half the corner angle. This calculator does that for you.
+Why are my baseboard corners gapping?
Almost always because the wall corner is not exactly 90°. Measure the real angle with a digital angle finder and use that number instead of assuming 45°. Caulk closes hairline gaps; anything wider needs a re-cut.
+Should I miter or cope inside corners?
Coping gives a tighter joint on inside corners that resists gapping when the trim shrinks, but it is slower. Mitering is faster and fine for painted MDF. Outside corners are always mitered.
+Do I need a bevel for baseboard?
No. Baseboard sits flat against the wall, so it is a flat miter — bevel stays at 0. Only sprung trim like crown needs a compound (bevel) cut.