Picture frame miter cuts
Enter the opening and the molding width. This gives the four cut lengths, long point to long point, and how much molding to buy.
in
in
in
Cut at 45.0°
Top / bottom
12"
Left / right
14"
Molding to buy
5.0 ft
Where to buy this
- 5.0 ft of moldingHome DepotLowe's
Feet of stock with the miters allowed for. Buy one length rather than two: a frame made from two sticks of the same profile shows the difference at a corner.
Plain search links, nothing sponsored. Prices and stock are the shop's, and a local lumberyard will usually beat both on solid stock.
The cut list
- Top and bottom, 2 piecesLong point to long point
- 12"
- Left and right, 2 piecesLong point to long point
- 14"
- Outer size
- 12" × 14"
- Molding to buyFor 1 frame, with corner waste
- 5.0 ft
About mitered frames
- Why is a rectangular frame always mitered at 45°?
- Because a square corner splits evenly between two pieces meeting there — half of 90° is 45° on each. Every rectangular frame takes the same setting regardless of its size, which is why 45° is the one miter angle stamped on the fence of almost every miter saw made.
- What does "long point to long point" mean?
- The length measured between the two outside corners of a mitered piece — the point of the 45° cut that reaches furthest, as opposed to the short point on the inside edge. It's the number you actually mark and cut to, because the short point is harder to reach with a square and easy to get wrong by the width of the blade kerf.
- Why does the top/bottom length equal the outer width?
- Because on a rectangle, the long point of each 45° miter lands exactly on the frame's outer corner. Follow the outside edge from one corner to the other and you've walked the full outer width — which is also the long-point-to-long-point length of that piece.
- How much extra molding should I buy?
- This adds 15% over the four exact lengths, which covers the triangular offcut at every miter and one or two re-cuts if a corner comes out a hair open. Buy a specific board length past the calculator's total when possible — you want any single piece to be long enough for one whole side, not stitched from two shorter offcuts.