Board Foot Calculator
1 board foot = 144 in³ = 1/12 ft³. Formula: BF = (L × W × T) / 144 (all dimensions in inches).
- Board foot definition: 1 BF = 144 in³ = 1/12 ft³.
- Formula: BF = (Length × Width × Thickness) / 144 when all dimensions are in inches.
- Mixed ft/in and m/cm inputs are converted to inches first, then used in the standard formula.
Use this Board Foot Calculator to estimate lumber volume and optional cost from the board thickness, width, length, and number of pieces.
Board Foot Formula
One board foot is equal to the volume of a board measuring 12 inches wide, 12 inches long, and 1 inch thick.
1 board foot = 144 cubic inches
When all dimensions are in inches:
Board feet = (thickness × width × length) ÷ 144
For multiple identical boards:
Total board feet = board feet per piece × number of pieces
When a price per board foot is entered:
Total cost = total board feet × price per board foot
Example
Suppose you have 5 boards that are 1.5 inches thick, 8 inches wide, and 96 inches long.
Board feet per piece = (1.5 × 8 × 96) ÷ 144 = 8 BF
Total board feet = 8 × 5 = 40 BF
If lumber costs $6 per board foot:
Total cost = 40 × $6 = $240
The five boards contain approximately 40 board feet of lumber.
Important Notes
- Board feet measure lumber volume, not surface area.
- Use the dimensions required for your estimate and select the correct units.
- Supplier measurement rules may differ from a simple dimensional calculation, especially for surfaced or hardwood lumber.
- Actual cost can also vary by species, grade, moisture content, surfacing, waste, and local pricing.