Board Foot Calculator
By Taro Schenker | Updated February 11, 2026
Quick Answer: To calculate board feet, multiply Thickness (in) x Width (in) x Length (ft) / 12. One board foot equals 144 cubic inches of wood. The lumber industry uses nominal dimensions (e.g. a 2x6 is calculated as 2 x 6, not the actual 1.5 x 5.5). Typical prices per BF: pine $3.50, oak $8, maple $7, cherry $10, walnut $12. Add 10-15% for waste. An 8-foot 2x6 contains 8 board feet.
Calculate how many board feet of lumber you need for your woodworking or construction project. Enter your board dimensions, choose a wood species for pricing, and get instant results including total board feet, waste-adjusted totals, and estimated cost.
What is a Board Foot?
A board foot is the standard unit of measure for lumber volume in the United States and Canada. One board foot equals a piece of wood that is 1 inch thick, 12 inches wide, and 1 foot long — or 144 cubic inches of wood. Lumber yards and hardwood dealers price their stock per board foot, making it essential to know how to calculate this unit when planning any woodworking or building project.
Board Foot Formula
The formula for calculating board feet is straightforward:
For example, a 2×6 board that is 8 feet long contains:
Note that the lumber industry uses nominal dimensions (the labeled size) for board foot calculations, not the actual milled dimensions. So a “2×6” is calculated as 2 inches by 6 inches even though it actually measures 1.5 by 5.5 inches.
Nominal vs Actual Lumber Sizes
When lumber is milled and dried, it shrinks from its rough-sawn nominal size. Here are the standard nominal sizes and their actual dimensions:
| Nominal Size | Actual Size (inches) | BF per 8' Board |
|---|---|---|
| 1 × 4 | 0.75 × 3.5 | 2.67 |
| 1 × 6 | 0.75 × 5.5 | 4.00 |
| 1 × 8 | 0.75 × 7.25 | 5.33 |
| 1 × 10 | 0.75 × 9.25 | 6.67 |
| 1 × 12 | 0.75 × 11.25 | 8.00 |
| 2 × 4 | 1.5 × 3.5 | 5.33 |
| 2 × 6 | 1.5 × 5.5 | 8.00 |
| 2 × 8 | 1.5 × 7.25 | 10.67 |
| 2 × 10 | 1.5 × 9.25 | 13.33 |
| 2 × 12 | 1.5 × 11.25 | 16.00 |
| 4 × 4 | 3.5 × 3.5 | 10.67 |
| 6 × 6 | 5.5 × 5.5 | 24.00 |
Lumber Prices by Species
Lumber prices vary significantly by wood species. Here are typical retail prices per board foot as a reference:
| Species | Type | Price per BF |
|---|---|---|
| Pine | Softwood | $3.50 |
| Poplar | Hardwood | $4.00 |
| Cedar | Softwood | $6.00 |
| Maple | Hardwood | $7.00 |
| Oak | Hardwood | $8.00 |
| Cherry | Hardwood | $10.00 |
| Walnut | Hardwood | $12.00 |
Prices are approximate retail averages and vary by region, grade, and supplier.
Tips for Buying Lumber
- Check moisture content: Kiln-dried lumber (6-8% MC) is more stable than air-dried (12-15% MC). Wet lumber will shrink and warp as it dries.
- Inspect each board: Look for warping, twisting, cupping, and excessive knots. Sight down the length of the board to check for straightness.
- Buy from hardwood dealers: For furniture-grade hardwoods, specialty lumber dealers offer better selection and prices per board foot than big-box stores.
- Order extra for waste: Add 10-15% to your calculated board feet to account for defects, saw kerf, and cutting mistakes.
- Consider rough-sawn lumber: Rough-sawn boards are cheaper per board foot than surfaced (S4S) lumber. If you have a planer, buying rough-sawn can save 20-30%.
- Buy in bulk: Many lumber yards offer volume discounts starting at 100 board feet. For large projects, ask about wholesale pricing.
Formula Summary
Board Foot Formula: To calculate board feet, multiply the Thickness (in) x Width (in) x Length (ft) and divide by 12. The lumber industry uses nominal dimensions by convention for pricing.
$$BF = \frac{T_{\text{in}} \times W_{\text{in}} \times L_{\text{ft}}}{12}$$
Total Board Feet: $$BF_{\text{total}} = BF_{\text{per board}} \times N_{\text{boards}}$$
Cost Formula: $$\text{Cost} = BF_{\text{adjusted}} \times \text{Price per BF}$$
| Nominal Size | Actual Size (in) | BF per 8' Board |
|---|---|---|
| 2 x 4 | 1.5 x 3.5 | 5.33 |
| 2 x 6 | 1.5 x 5.5 | 8.00 |
| 2 x 8 | 1.5 x 7.25 | 10.67 |
| 2 x 10 | 1.5 x 9.25 | 13.33 |
| 2 x 12 | 1.5 x 11.25 | 16.00 |
| Wood Species | Price per BF |
|---|---|
| Pine | $3.50 |
| Poplar | $4.00 |
| Cedar | $6.00 |
| Maple | $7.00 |
| Oak | $8.00 |
| Cherry | $10.00 |
| Walnut | $12.00 |
Standard Assumptions: Board foot calculations use nominal dimensions by industry convention. Waste factor of 10% accounts for defects, saw kerf, and cutting errors. 1 board foot = 144 cubic inches.
Related Calculators
- Plywood Calculator — calculate how many plywood sheets you need
- Deck Board Calculator — estimate decking boards for your project
- Cubic Yard Calculator — convert any dimensions to cubic yards
Estimates are for planning purposes only. Consult a qualified contractor for critical projects. Actual material requirements may vary based on site conditions, waste, and installation methods.
Pricing last verified: February 2026. Material prices vary by region, season, and supplier. Prices shown are national averages for planning purposes.