Calculate board feet for hardwood lumber. Enter the thickness, width, and length to get board feet per board and the total.
Usage Tip
Quarter notation gives thickness in quarter-inches: 4/4 = 1″, 6/4 = 1.5″, 8/4 = 2″. Buy 15 to 20% extra hardwood for knots, checks, and planing loss.
(same as T × W × L ÷ 144 with length in inches)
Total = board feet × quantity
Use nominal dimensions (a 4/4 board counts as 1″ thick) since that is how lumber is sold.
Lumber is priced on nominal (rough) thickness — a 4/4 board is 1″ for pricing even though it planes down to about 13/16″.
Round board-foot counts up and add waste for defects, planing, and trimming — rough lumber rarely yields 100%.
What Is a Board Foot?
A board foot is the standard unit for measuring hardwood lumber volume – one board foot equals a piece 1 inch thick, 12 inches wide, and 12 inches long (144 cubic inches). It is how sawmills and lumber yards price rough hardwood, so knowing your board footage is the difference between ordering the right amount of walnut and badly overspending. The calculator above turns board dimensions and quantity into board feet, waste-adjusted totals, and cost.
Board Foot Formula
Use nominal dimensions in inches for thickness and width, and length in feet. A 1 × 6 board, 8 ft long: (1 × 6 × 8) ÷ 12 = 4 board feet. If you measure length in inches instead, divide by 144 rather than 12.
Common Board Foot Table
| Board size | Length | Board feet |
|---|---|---|
| 1×4 | 8 ft | 2.67 BF |
| 1×6 | 8 ft | 4 BF |
| 1×8 | 8 ft | 5.33 BF |
| 2×4 | 8 ft | 5.33 BF |
| 2×6 | 10 ft | 10 BF |
| 4×4 | 8 ft | 10.7 BF |
Lumber Estimating Guide
Estimate a project by listing each part, its rough dimensions, and how many you need, then total the board feet and add waste. Buy in the thickness sold by quarters – 4/4 (1 inch), 6/4 (1.5 inch), 8/4 (2 inch) – and remember rough boards come oversized so you can surface them flat. Always round up; lumber is easier to have left over than to re-source mid-build in a matching color and grain.
Rough vs Finished Lumber (Nominal vs Actual)
Softwood is sold by nominal size, which is larger than the actual dressed size. Hardwood board feet are figured at the rough/nominal thickness even after surfacing. Common differences:
| Nominal | Actual (surfaced) |
|---|---|
| 1×4 | 3/4" × 3-1/2" |
| 1×6 | 3/4" × 5-1/2" |
| 2×4 | 1-1/2" × 3-1/2" |
| 2×6 | 1-1/2" × 5-1/2" |
| 4×4 | 3-1/2" × 3-1/2" |
Board-foot pricing uses the nominal dimension, so a surfaced 4/4 board is still billed as a full inch thick.
Hardwood Pricing Guide
Hardwood is priced per board foot, and the spread between species is large. Pricing examples at roughly typical retail (varies widely by region, grade, and width):
| Species | Typical $/BF | 10 BF costs |
|---|---|---|
| Poplar | $4 | $40 |
| Red oak | $6 | $60 |
| Hard maple | $7 | $70 |
| White oak | $8 | $80 |
| Cherry | $8 | $80 |
| Walnut | $12 | $120 |
Species Comparison
| Species | Hardness | Typical use |
|---|---|---|
| Poplar | Soft hardwood | Paint-grade, interior trim |
| Red / white oak | Hard | Furniture, flooring, cabinets |
| Hard maple | Very hard | Workbenches, cutting boards, floors |
| Cherry | Medium | Fine furniture, cabinetry |
| Walnut | Medium-hard | Premium furniture, accents |
| Pine (softwood) | Soft | Construction, shelving, utility |
Woodworking Material Planning
Rough board-foot ranges for common projects (before waste) help you sanity-check an order:
| Project | Approx. board feet |
|---|---|
| Bookshelf / shelving unit | 15–25 BF |
| Dining table | 25–40 BF |
| Workbench | 25–40 BF |
| Base cabinet | 40–60 BF |
Sawmill Lumber Guide
Buying direct from a sawmill is the cheapest way to get hardwood, but it comes rough-sawn and often air- or kiln-dried to varying degrees. Expect full nominal thickness (sometimes a hair over), live edges, and the need to joint and plane. Factor extra board feet for jointing waste and for culling boards with checks, knots, or excessive warp.
Lumber Waste Guide
Always order more than your net board feet. Recommended waste factors: 10% for simple, straight cuts in dimensional lumber; 15–20% for hardwood furniture where you match grain and cut around defects; 25%+ for rough sawmill stock or highly figured boards. Wide or long parts and species with frequent defects push the factor higher.
Common Estimating Mistakes
- Forgetting waste – net board feet is not what you buy.
- Using actual surfaced dimensions instead of nominal for pricing.
- Measuring length in inches but dividing by 12 (use 144 for inches).
- Ignoring defects and grain matching on hardwood.
- Underestimating thick stock – 8/4 doubles the board feet of 4/4.
Frequently Asked Questions
What is a board foot?
A volume unit equal to a board 1 in thick by 12 in wide by 12 in long (144 cubic inches). It is how hardwood is priced.
How do I calculate board feet?
Board feet = (thickness in inches × width in inches × length in feet) ÷ 12. Multiply by quantity, then add a waste factor.
How many board feet in a 2×4×8?
(2 × 4 × 8) ÷ 12 = 5.33 board feet.
What is the board foot formula?
(T × W × L) ÷ 12 with T and W in inches and L in feet, or divide by 144 if length is in inches.
What is the difference between nominal and actual size?
Nominal is the called size (2×4); actual is the smaller surfaced size (1-1/2" × 3-1/2"). Board feet are figured on nominal.
How much does a board foot of walnut cost?
Roughly $10–14 at typical retail, versus about $4 for poplar – species choice drives the cost more than anything.
Related Lumber Calculators
Note: nominal lumber sizes are larger than actual surfaced dimensions, and rough sawmill stock varies; board-foot pricing here uses nominal dimensions. Prices are rough estimates that vary by region, grade, width, and supplier. Always add a waste factor and confirm pricing with your lumber yard. General guidance, not a quote.