Woodworking calculators

Free woodworking calculators: board feet, inches to millimeters, cut lists, miter angles, finish coverage, wood moisture, wood movement and equal spacing. The math is shown on every page.

I built these so I stop doing math on a napkin before going to the lumberyard. They are plain math: each page explains the formula and links the source. They save nothing and keep working offline once loaded.

• Board foot calculator

  Board feet from thickness, width and length, in inches or millimeters, plus the cost if you know the price per board foot. The formula is on the page so you can check it.

• Inches to mm converter

  Type 3/4, 1 1/2 or 0.375 and get millimeters. Or type millimeters and get the nearest 1/16, 1/32 or 1/64 inch. With a full fraction table.

• Cut list calculator

  List the part lengths you need and the length of the boards you can buy. It packs the parts onto as few boards as it can, counts the saw kerf, and draws each board.

• Miter angle calculator

  Pick the number of sides and get the miter saw setting, the angle from the edge, and the long-point and short-point length of each piece. Square frames, hexagons, octagons.

• Finish coverage calculator

  Surface area from your part sizes, times coats, divided by the coverage printed on the can. Liters or gallons, so you buy one can and not three.

• Wood equilibrium moisture calculator

  Type the air temperature and relative humidity and get the moisture content wood settles at, with the USDA Wood Handbook equation. Compare two seasons to see how much your wood will swing.

• Wood movement calculator

  Pick the species, the cut and the width, then the moisture content now and later. Get the change in width from the shrinkage values in the USDA Wood Handbook, for tabletops, panels and drawers.

• Equal spacing calculator

  Total length, how many pieces and how wide they are: get the gap between them and where to mark each one, in millimeters or inches with fractions.

How I work