ProjectCalc (working name)

Board Foot Calculator

Board feet and lumber cost from board dimensions — plus a printable cost worksheet for the lumber desk.

Inches — fractions welcome: 5 1/2
Feet: 8 or 8' 6"
15–20% is standard for rough lumber selection and defects

Lumber cost worksheetValue
Board feet per board
Board feet (boards only)
Board feet to buy (with allowance)

✅ Buying checklist

  • Sight down every board: reject bow, crook, twist and end splits
  • Ask whether the price is for surfaced (S2S/S4S) or rough — and net or gross tally
  • Acclimate hardwood in the shop 1–2 weeks before milling
  • Keep the receipt — matching a second run to the same stack matters for color

How the math works

One board foot = 144 cubic inches of wood: (thickness ″ × width ″ × length ft) ÷ 12, or (thickness × width × length in inches) ÷ 144. Nominal sizes lie — a "2×4" is 1.5″ × 3.5″ actual. For rough lumber sold by the board foot, use the *nominal* thickness the yard tallies by (4/4, 5/4, 8/4) and the actual width and length.

For estimation only. Yard tally rules vary (some round each board up); confirm before a large order.