Board Feet Calculator
Calculate board feet for a single board or your entire project cut list. Set a waste percentage, get your lumber order quantity, and optionally estimate material cost — all in one tool. Includes the board feet formula, worked examples, and a quick-reference table for common sizes including 2×4, 4×4, 1×6, and 8/4 hardwood.
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Board feet, lumber cost, compound miter angles, and unit conversion — all four calculators in one hub. After calculating board feet, use the lumber cost calculator to price your order.
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On this page: Calculator · The formula · Waste factor guide · Nominal vs actual sizes · Quick reference table · FAQs
Board feet calculator
Enter the dimensions of one board to get its board-foot volume instantly.
Free to use — no sign-up required. Some links on this page are affiliate links — see our disclosure.
How to calculate board feet: the formula explained
A board foot is a unit of lumber volume equal to 144 cubic inches — the equivalent of a piece 1 inch thick, 12 inches wide, and 12 inches long. The formula is:
Board feet = (thickness × width × length) ÷ 144 (all dimensions in inches)
If you measure length in feet instead of inches, divide by 12 instead of 144:
Board feet = (thickness × width × length in feet) ÷ 12
Worked examples
| Board | Thickness | Width | Length | Calculation | Board feet |
|---|---|---|---|---|---|
| 1×6 at 8 ft | 1″ | 6″ | 8 ft | (1 × 6 × 8) ÷ 12 | 4.00 bf |
| 1×4 at 6 ft | 1″ | 4″ | 6 ft | (1 × 4 × 6) ÷ 12 | 2.00 bf |
| 2×4 at 8 ft | 2″ | 4″ | 8 ft | (2 × 4 × 8) ÷ 12 | 5.33 bf |
| 4/4 walnut, 5″ wide, 7 ft | 1″ | 5″ | 7 ft | (1 × 5 × 7) ÷ 12 | 2.92 bf |
| 8/4 maple slab, 10″ wide, 5 ft | 2″ | 10″ | 5 ft | (2 × 10 × 5) ÷ 12 | 8.33 bf |
Understanding hardwood lumber thickness notation
Hardwood lumber is often described in quarters of an inch: 4/4 (four-quarter) means 1 inch thick, 5/4 means 1¼ inches, 6/4 means 1½ inches, 8/4 means 2 inches. This is the rough-sawn thickness before surfacing. After surfacing, a 4/4 board is typically ¾″ to 13⁄16″; an 8/4 board is typically 1¾″. When calculating board feet for pricing purposes, use the rough-sawn (nominal) thickness, since that is what the yard charges for. When calculating for joinery or fit, use the actual surfaced thickness.
Waste factor guide: what percentage to use
The waste factor is not an estimate or a safety buffer — it is a specific correction for real material loss that occurs in every woodworking project. Using the wrong percentage means either buying too little (and making a second trip to the yard, if the same batch is even still available) or tying up money in excess lumber you will not use.
| Situation | Recommended waste % | Why |
|---|---|---|
| CNC or laser projects | 8–12% | Digital nesting minimises offcuts. Most loss is from fixed margins and test pieces. |
| Clear S4S hardwood, straight cuts | 12–15% | Surfaced-four-sides boards have minimal defects. Waste is mainly from cross-cut ends and saw kerf. |
| Standard project, mixed cuts | 18–20% | A combination of rips, cross-cuts, angled cuts, and some defect avoidance. Use as default. |
| Rough-sawn lumber from a sawyer or mill | 25–30% | Significant material lost to surfacing (planing and jointing), wane on edges, and checking at ends. |
| Highly figured or expensive exotic species | 20–25% | You will cut around colour streaks, mineral inclusions, and wild grain more carefully — smaller usable parts, more offcuts. |
| Projects with many small parts (chairs, boxes) | 25–30% | Small parts mean short offcuts that can't be reused. Each cross-cut end wastes more proportionally than on long parts. |
When in doubt, round up to 20% and buy a little more than you need. The cost of one extra board foot is far lower than the cost of a second order, second delivery, or discovering the yard sold the rest of the batch.
Nominal vs actual lumber dimensions
This is the most frequent source of calculation error for beginners. Dimensional softwood at a home centre — the 2×4s, 1×6s, and 2×8s on the rack — is sold by nominal size but has smaller actual dimensions after drying and surfacing.
| Nominal size | Actual size | Board feet per linear foot | Board feet at 8 ft |
|---|---|---|---|
| 1×2 | ¾″ × 1½″ | 0.094 bf/lf | 0.75 bf |
| 1×3 | ¾″ × 2½″ | 0.156 bf/lf | 1.25 bf |
| 1×4 | ¾″ × 3½″ | 0.219 bf/lf | 1.75 bf |
| 1×6 | ¾″ × 5½″ | 0.344 bf/lf | 2.75 bf |
| 1×8 | ¾″ × 7¼″ | 0.453 bf/lf | 3.63 bf |
| 1×10 | ¾″ × 9¼″ | 0.578 bf/lf | 4.63 bf |
| 1×12 | ¾″ × 11¼″ | 0.703 bf/lf | 5.63 bf |
| 2×4 | 1½″ × 3½″ | 0.438 bf/lf | 3.50 bf |
| 2×6 | 1½″ × 5½″ | 0.688 bf/lf | 5.50 bf |
| 2×8 | 1½″ × 7¼″ | 0.906 bf/lf | 7.25 bf |
| 4×4 | 3½″ × 3½″ | 0.854 bf/lf | 6.83 bf |
Which dimensions to use in the calculator: For pricing and ordering hardwood, use the nominal (rough) dimensions — you are paying for the full volume before surfacing. For planning joinery and fit, use actual dimensions. Softwood from a home centre is charged by the piece, not board foot, so use actual dimensions if you are trying to calculate volume.
Board feet quick reference: common lumber sizes
The table below shows board feet per linear foot and total board feet for standard lengths using nominal dimensions — useful as a quick lookup when you are at the yard without your phone calculator.
| Nominal size | bf / linear ft | 6-foot board | 8-foot board | 10-foot board | 12-foot board |
|---|---|---|---|---|---|
| 1×4 | 0.33 | 2.00 bf | 2.67 bf | 3.33 bf | 4.00 bf |
| 1×6 | 0.50 | 3.00 bf | 4.00 bf | 5.00 bf | 6.00 bf |
| 1×8 | 0.67 | 4.00 bf | 5.33 bf | 6.67 bf | 8.00 bf |
| 1×10 | 0.83 | 5.00 bf | 6.67 bf | 8.33 bf | 10.00 bf |
| 1×12 | 1.00 | 6.00 bf | 8.00 bf | 10.00 bf | 12.00 bf |
| 4/4 hardwood (1″), 6″ wide | 0.50 | 3.00 bf | 4.00 bf | 5.00 bf | 6.00 bf |
| 4/4 hardwood (1″), 8″ wide | 0.67 | 4.00 bf | 5.33 bf | 6.67 bf | 8.00 bf |
| 5/4 hardwood (1.25″), 6″ wide | 0.63 | 3.75 bf | 5.00 bf | 6.25 bf | 7.50 bf |
| 8/4 hardwood (2″), 6″ wide | 1.00 | 6.00 bf | 8.00 bf | 10.00 bf | 12.00 bf |
| 8/4 hardwood (2″), 8″ wide | 1.33 | 8.00 bf | 10.67 bf | 13.33 bf | 16.00 bf |
Bookmark this page or print this table for use at the lumber yard — it saves recalculating common sizes by hand. For a board not in this table, use the calculator above.
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Board feet calculator FAQs
How do you calculate board feet?
Board feet = (thickness in inches × width in inches × length in inches) ÷ 144. If measuring length in feet: (thickness × width × length) ÷ 12. For a 1″ × 6″ × 8-foot board: (1 × 6 × 8) ÷ 12 = 4 board feet. Use the calculator above for multiple boards and automatic waste calculation.
What waste percentage should I use?
15% for clear S4S hardwood with straight cuts. 20% as a general-purpose default. 25% for rough-sawn lumber. 8–12% for CNC or laser projects with digital nesting. The waste factor accounts for defects you cut around, surfacing loss, saw kerf, and end splits — it is not a cushion, it is a real correction.
What is the difference between nominal and actual lumber dimensions?
Nominal dimensions are the trade names (1×6, 2×4). Actual dimensions are smaller after drying and surfacing — a 1×6 is actually ¾″ × 5½″. For hardwood pricing, use nominal (rough) dimensions. For joinery planning, use actual dimensions. See the nominal vs actual table above.
How many board feet is a typical woodworking project?
Rough estimates (before waste): small side table 8–12 bf, dining chair 10–15 bf, bookcase 20–35 bf, dining table top 15–25 bf, bed frame 40–60 bf, small cabinet 25–40 bf. Enter your actual cut list dimensions into the project mode calculator for a precise figure.
Can I use this calculator for sheet goods like plywood?
Sheet goods are sold by the sheet (typically 4×8 ft = 32 sq ft), not by board foot. You can calculate the volume of sheet material using the formula, but it is more practical to count sheets: divide your total area needed by 32 and round up. For MDF or melamine on a CNC, use the board feet calculator as a nesting guide — how much material you need to cut — and then convert to sheets.
What is the board feet formula in fraction of an inch?
The formula is the same — just convert fractions to decimals first. ¾″ = 0.75, 1¼″ = 1.25, 1½″ = 1.5, 1¾″ = 1.75, 2½″ = 2.5. The calculator accepts decimal inputs and handles the conversion internally. For example, a ¾″ × 5½″ × 8-foot board: (0.75 × 5.5 × 8) ÷ 12 = 2.75 board feet.