Board Foot Calculator
Use this board foot calculator to total lumber from thickness, width, length and piece count. Add different board sizes and an optional price, using measured dimensions or the dimensions your supplier bills.
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How to Calculate Board Feet
One board foot (BF) is 144 cubic inches: the volume of a board 1 inch thick, 12 inches wide and 12 inches long. It measures wood volume, not the number of boards.
When every dimension is in inches, divide by 144 instead of 12. This board feet calculator works out each different size separately, then adds the results. Use straight, rectangular board dimensions; do not include air gaps between stacked boards.
Worked example: six boards, each 1.25 in thick × 7 in wide × 9 ft long, contain 6.5625 BF each and 39.375 BF in total. The Load example button enters these measurements without a price. They are stated dimensions for this example, not a nominal lumber conversion.
Which Dimensions Should You Enter?
For physical volume, use the board's measured thickness, width and length. For a purchase estimate, use the dimensions behind the supplier's quoted board footage. A nominal label and a surfaced board can describe the same piece with different numbers.
For example, Woodworkers Source uses the hardwood thickness name when tallying its boards, even if the surfaced thickness is smaller. Confirm your seller's practice before pricing; this lumber board foot calculator uses exactly what you enter and applies no automatic surfacing or tally-rounding rule.
| Thickness name | Nominal inches |
|---|---|
| 4/4 | 1 |
| 5/4 | 1.25 |
| 6/4 | 1.5 |
| 8/4 | 2 |
Choose Supplier's tally size to label a commercial estimate. That selection changes the stated basis, not your entered dimensions. Board footage alone does not tell you which finished parts will fit after cuts, defects or surfacing.
Board Foot Chart for Common Sizes
This chart uses the listed nominal thickness and width, one board per cell, with no extra allowance. Use measured values in the form if you need the volume of a dressed piece.
| Nominal size (in) | 8 ft long | 10 ft long | 12 ft long |
|---|---|---|---|
| 1 × 6 | 4 | 5 | 6 |
| 1 × 8 | 5.333 | 6.667 | 8 |
| 2 × 4 | 5.333 | 6.667 | 8 |
| 2 × 6 | 8 | 10 | 12 |
| 2 × 8 | 10.667 | 13.333 | 16 |
How many board feet are in a 2×4×10?
Using 2 in × 4 in × 10 ft gives 6.667 BF. If your piece measures 1.5 in × 3.5 in × 10 ft, its measured volume is 4.375 BF. These answers use different dimensions; match the basis to the job or quote.
Board Foot Price Calculator
Enter a quoted rate under Lumber price to multiply the total board feet by that rate. Use the supplier's tally dimensions when estimating a bill, and keep differently priced wood in separate calculations.
For a price per MBF: material subtotal = total BF ÷ 1,000 × price per MBF
At a hypothetical $6.40 per BF, the 39.375 BF example costs $252. A quote of $6,400 per MBF gives the same subtotal. Tax, delivery, machining charges and seller-specific rounding are excluded. No market price or waste percentage is assumed.
Can You Convert Board Feet to Square Feet?
Yes, if you know the thickness: face area (ft²) = BF ÷ thickness (in). For example, 20 BF at 2 inches thick has 10 ft² of broad-face area. Mixed thicknesses must be converted row by row, and tongues, overlaps or deck gaps can make installed coverage different.
Sources & Methodology
Rectangular sawn lumber only. Standing trees and round logs require a separate log-scaling method; this tool does not estimate sawmill recovery, cutting layouts, weight or structural capacity. Totals use unrounded row values; displayed board footage uses up to three decimals. Very small nonzero results use significant figures.
1 BF = 144 in³ = 1/12 ft³ = 0.002359737216 m³. Metric inputs are converted using 1 in = 25.4 mm and 1 ft = 0.3048 m. If you enter tally sizes, the volume equivalents describe that tally basis, not necessarily the physical wood.
- Penn State Extension — board-foot formula and the separate role of log rules
- American Hardwood Export Council — hardwood measurement
- Woodworkers Source — an example of a retailer's tally convention
- NIST — exact length conversions
Sources reviewed October 26, 2026.
