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.

Check hardwood & lumber supplies

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

Reference: Penn State Extension — board-foot calculation.

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

Waste allowances are planning estimates, not industry standards. The right percentage depends on stock quality, defects, grain selection, kerf, surfacing, part size, and how efficiently the cut list can be nested. Use the ranges below as starting points, then adjust them to the actual lumber and project.

Situation Planning starting point 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. Adjust to your cut list.
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 uncertain, model a few allowances in the calculator and compare the order quantity. For expensive or visually matched stock, confirm availability and defects before choosing a final buffer.

Nominal vs actual lumber dimensions

Dimensional softwood is commonly named by a nominal size even though the surfaced piece is smaller. For example, a nominal 2×4 is commonly 1½″ × 3½″ actual size. That distinction matters when you are calculating physical volume or planning joinery.

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

Reference: NIST — SI units and dimensional measurement guidance.

Which dimensions to use in the calculator: For supplier pricing, use the dimensions or board-foot convention your lumber yard uses. For joinery and physical-volume planning, use the actual measured dimensions. Retail dimensional softwood is commonly sold by piece or length rather than priced as hardwood board-foot stock.

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.

Where to buy hardwood lumber

Once you have your board feet order quantity, you have several options depending on species, quality, and location. The best choice depends on whether you need specific species, are comfortable with rough-sawn stock, or need the convenience of pre-surfaced boards.

Specialist hardwood dealers offer the widest species selection, better quality control, and staff who can help you select boards. They stock rough-sawn and S4S (surfaced four sides) in 4/4 through 16/4 thicknesses. Rockler is one of the largest retail chains with consistent stock and the option to order online for in-store pickup.

Since nominal and actual dimensions differ, it's worth checking boards with your own tape and square at the yard rather than trusting the rack label alone — especially on rough-sawn stock where actual thickness can vary board to board.

Speed squares for checking dimensions ↗

Home centres (Home Depot, Lowe's, Menards) stock dimensional pine and construction-grade lumber by the piece. Selection is limited but prices are lower for softwood projects. Hardwood availability varies significantly by location.

Local sawyers and small mills are the best source for air-dried slabs, unusual species, and locally sourced material. Pricing is often lower than retail dealers for rough-sawn stock, but you will need a jointer and planer to process it, and waste percentages are higher.

For projects requiring precise material cost calculation before buying, use the lumber cost calculator to price your full order — it handles multiple species at different prices per board foot. If you're selling your work, see how to make money woodworking for pricing strategies and the most profitable project categories. Planning a specific build? See miter saw station plans for a shop cabinet project, or woodworking jewelry box plans for a small-material first project.

Affiliate disclosure: Some links on this page (marked with "sponsored") are affiliate links. If you click through and make a purchase, WoodworkingTraining.com earns a small commission at no extra cost to you. This does not affect which retailers are recommended. See the full disclaimer.

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?

There is no universal waste percentage. As planning starting points, you might use roughly 8–12% for efficiently nested digital work, 12–15% for clean surfaced stock with simple cuts, 18–20% for mixed cuts, and 20–30% when defects, rough stock, grain selection, or many small parts increase loss. Adjust the allowance to the actual stock and cut list.

What is the difference between nominal and actual lumber dimensions?

Nominal dimensions are trade names such as 1×6 or 2×4; actual surfaced dimensions can be smaller after drying and surfacing. For example, a nominal 2×4 is commonly 1½″ × 3½″. Use the dimensions your lumber supplier uses for board-foot pricing, and use actual measured dimensions for joinery or physical-volume calculations.

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 normally planned by sheet area and part layout rather than board feet. Use the plywood calculator for an area-based sheet estimate. For cabinets, furniture, MDF, melamine, or other rectangular panel parts, use the cut list optimizer to account for part sizes, kerf, rotation, and grain direction.

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.