Free Board Foot Calculator & Lumber Estimator
Accurate lumber volume calculation, $/BF cost estimation, Doyle log yield scaling, and timber conversion tools for woodworkers, sawyers, and builders.
What Is a Board Foot?
A board foot (BF) is a standardized unit of volume used in the lumber and timber industry to measure rough-sawn hardwood and softwood. One board foot represents a piece of wood that is 1 inch thick, 12 inches wide, and 12 inches long, equaling exactly 144 cubic inches.
Board Foot Formulas
- When length is in feet:
Board Feet = (Thickness in inches × Width in inches × Length in feet) ÷ 12
- When length is in inches:
Board Feet = (Thickness in inches × Width in inches × Length in inches) ÷ 144
- Material Cost:
Total Lumber Cost = Total Board Feet × Price per Board Foot ($/BF)
- Wholesale MBF:
MBF (Thousand Board Feet) = Total Board Feet ÷ 1,000
Standard 2x4, 2x6, 2x8 Board Foot Reference Chart
| Lumber Size |
8 Ft Length |
10 Ft Length |
12 Ft Length |
16 Ft Length |
| 2x4 Lumber |
5.33 BF |
6.67 BF |
8.00 BF |
10.67 BF |
| 2x6 Lumber |
8.00 BF |
10.00 BF |
12.00 BF |
16.00 BF |
| 2x8 Lumber |
10.67 BF |
13.33 BF |
16.00 BF |
21.33 BF |
| 4x4 Post |
10.67 BF |
13.33 BF |
16.00 BF |
21.33 BF |
Lumber Sizing: The Quarter System (4/4, 5/4, 8/4)
Rough-sawn hardwood is graded and sold using the quarter system based on rough thickness before surfacing (S2S or S4S):
- 4/4 (Four-Quarter): 1 inch rough thickness (surfaces to approx. 13/16" or 3/4")
- 5/4 (Five-Quarter): 1.25 inches rough thickness (surfaces to approx. 1-1/16")
- 6/4 (Six-Quarter): 1.5 inches rough thickness (surfaces to approx. 1-5/16")
- 8/4 (Eight-Quarter): 2 inches rough thickness (surfaces to approx. 1-3/4")
- 12/4 (Twelve-Quarter): 3 inches rough thickness (heavy turning & leg stock)