Utilix knowledge base
What Is a Board Foot? Lumber Measurement Explained
Published Jun 16, 2026
A board foot (BF) is the standard unit of measurement for hardwood lumber volume. It represents the volume of a piece of wood that is 1 inch thick, 12 inches wide, and 12 inches long — 144 cubic inches. Understanding board feet is essential for pricing lumber, estimating project costs, and communicating with lumber yards.
Use the Board Foot Calculator to quickly find board feet for any lumber size.
The Formula
Board feet = (Thickness × Width × Length in feet) ÷ 12
Where thickness and width are in inches, and length is in feet.
Examples:
| Board size | Calculation | Board feet |
|---|---|---|
| 1" × 6" × 8ft | (1 × 6 × 8) ÷ 12 | 4 BF |
| 1" × 12" × 8ft | (1 × 12 × 8) ÷ 12 | 8 BF |
| 2" × 6" × 10ft | (2 × 6 × 10) ÷ 12 | 10 BF |
| 4/4 × 8" × 6ft | (1 × 8 × 6) ÷ 12 | 4 BF |
| 8/4 × 8" × 6ft | (2 × 8 × 6) ÷ 12 | 8 BF |
Nominal vs Actual Dimensions
This is the biggest source of confusion for new woodworkers.
Nominal dimensions are the named size — what you ask for at the lumber yard. A "1×6" is nominally 1 inch thick and 6 inches wide.
Actual dimensions are what you actually get after surfacing (planing). A nominal 1×6 actually measures about 0.75" × 5.5".
| Nominal | Actual |
|---|---|
| 1" thick | ¾" (0.75") |
| 2" thick | 1½" (1.5") |
| 4" (4×4) | 3½" × 3½" |
| 6" wide | 5½" |
| 8" wide | 7¼" |
For board foot pricing at a lumber yard, use nominal dimensions — that's how lumber yards calculate what they charge you, regardless of actual thickness. For cutting lists and joinery, use actual dimensions.
Hardwood Thickness in Quarters
Hardwood lumber is often described in quarters of an inch:
| Quarter notation | Thickness (nominal) | Rough actual | Surfaced actual |
|---|---|---|---|
| 4/4 (four-quarter) | 1" | ~1.125" rough | ~0.75–0.875" |
| 5/4 (five-quarter) | 1.25" | ~1.375" rough | ~1.0–1.125" |
| 6/4 (six-quarter) | 1.5" | ~1.625" rough | ~1.25–1.375" |
| 8/4 (eight-quarter) | 2" | ~2.125" rough | ~1.75" |
| 12/4 (twelve-quarter) | 3" | ~3.125" rough | ~2.75" |
Rough-sawn lumber has extra thickness that disappears after milling. This is normal and expected.
Softwood Lumber: Linear Feet Instead
Softwood dimensional lumber — the 2×4s, 2×6s, and 2×8s used in framing and construction — is sold by the linear foot at most home centers (Lowe's, Home Depot), not by board feet. However, contractors and timber suppliers still quote large softwood orders in board feet.
To convert between the two:
Board feet = (Nominal thickness × Nominal width × Length in feet) ÷ 12
A single 2×4×8ft stud = (2 × 4 × 8) ÷ 12 = 5.33 board feet.
Adding Waste Allowance
No project uses 100% of the wood you buy. Always add a waste factor:
| Project type | Recommended waste |
|---|---|
| Clear, kiln-dried hardwood | 10–15% |
| Select/better softwood | 10% |
| Knotty or common grade | 15–20% |
| Reclaimed or rough-sawn | 20–25% |
| Complex joinery / tight fits | 20–25% |
Waste accounts for end splits, knots in load-bearing positions, milling tearout, mis-cuts, and layout optimisation losses.
Calculating Project Cost
Once you have total board feet (with waste), multiply by the price per board foot:
Total cost = Board feet × Price per BF
Hardwood prices (2026 reference, US domestic species):
- Poplar: $3–5/BF (budget option, paint-grade)
- White oak: $7–12/BF (popular for furniture and cabinets)
- Hard maple: $7–10/BF (kitchen tops, cutting boards)
- Walnut: $12–20/BF (premium furniture)
- Cherry: $10–16/BF (heirloom furniture)
- Exotic species (Teak, Mahogany): $20–50+/BF
Prices fluctuate with lumber markets, shipping, and regional availability. Always get a quote from your local lumber yard before finalising a project budget.
Tips for Buying Lumber
- Buy extra on your first project — it's cheaper to return unused boards than to make a second trip mid-project
- Inspect boards in person — check for cupping, bowing, twisting, and checking (cracks on the ends)
- Let lumber acclimate — new lumber may be drier or wetter than your shop; let it sit in your workspace for a few days before milling
- End-seal reclaimed lumber — exposed ends dry faster and crack; seal them with wax or PVA glue during acclimation
Use the Board Foot Calculator to total up your cutting list before heading to the lumber yard.