Calculate board feet for lumber from thickness, width, length and quantity — single boards, full cut lists, or a reverse calculator for a target board-foot total.
Quarter notation (4/4, 8/4…) describes rough-sawn thickness convention, not grain orientation (that's "quarter-sawn," a different concept). Surfaced/planed boards finish thinner — enter your board's actual measured thickness for an exact result.
Waste & Cost (optional)
10% is a common starting point, not a universal figure — appropriate waste depends on knots, checks, sapwood, grain selection, defects, board width variation, milling, jointer/planer loss, saw kerf, project layout, species and grade.
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Written and reviewed by Mohsin Iqbal · Last reviewed August 2026
A board foot is a unit of lumber volume equal to 144 cubic inches — the same volume as a board 1 inch thick, 12 inches wide and 12 inches long. Board feet are commonly used to measure and price hardwood and rough-sawn lumber in the United States, since the unit accounts for thickness as well as area, unlike square feet.
Multiply thickness in inches by width in inches by length in feet, then divide by 12. If your length is already in inches instead, divide by 144 instead of 12. This calculator handles either automatically, and lets thickness, width and length each use their own unit — enter measurements in whatever units you have them, mixed or matched, and it converts internally.
Board Feet = Thickness(in) × Width(in) × Length(ft) ÷ 12
— or, if length is in inches —
Board Feet = Thickness(in) × Width(in) × Length(in) ÷ 144
Both formulas are exactly equivalent — 12 inches per foot combined with the second formula's larger divisor accounts for the same unit difference. 1 board foot = 144 cubic inches = 1/12 cubic foot.
This calculator supports three modes: a single board (or several identical boards), a full cut list for projects using different board sizes, and a reverse calculator for working out how many boards you need to hit a target board-foot total.
Measure actual thickness, width and length directly with a tape measure or calipers — don't assume nominal lumber sizes (like "2×6") match what you're holding, since surfaced lumber is milled down from its rough-sawn starting size. Enter what you actually measured; this calculator never substitutes an assumed nominal size for your input.
For identical boards, board feet per board multiplied by quantity gives the total. For a project using several different board sizes, use the cut-list mode: enter each distinct board size and quantity as its own row, and the calculator sums every row into a project subtotal.
Enter a price per board foot to see estimated material cost, both before and after your waste allowance. Lumber pricing conventions vary by supplier and species — some quote by the board foot, others by the linear foot or by the piece, so confirm which convention your supplier uses before comparing prices.
Quarter notation describes rough-sawn lumber thickness in quarters of an inch: 4/4 means four-quarters, or 1 inch. This is a completely different concept from "quarter-sawn," which describes how a log was sawn relative to its grain — the two terms sound similar but aren't related.
| Designation | Rough thickness |
|---|---|
| 4/4 | 1″ |
| 5/4 | 1¼″ |
| 6/4 | 1½″ |
| 8/4 | 2″ |
| 10/4 | 2½″ |
| 12/4 | 3″ |
| 16/4 | 4″ |
Actual surfaced thickness can be less after drying, planing and finishing — a board sold as 8/4 rough might finish at 1¾″ or less once surfaced on both faces. These presets set the thickness field to the rough figure as a starting point; if you know your board's actual finished thickness, enter that instead.
Rough lumber comes straight from the sawmill at its full sawn thickness. Finished (surfaced) lumber has been planed smooth on one or more faces, removing material and reducing thickness — commonly ⅛″ to ¼″ per surfaced face. Board footage is sometimes priced on the rough (pre-surfacing) dimension even when you're buying surfaced material, so check which convention your supplier uses.
Linear feet measures only length, ignoring thickness and width entirely — useful for trim or molding sold by the running foot, but meaningless for comparing lumber of different cross-sections. Board feet accounts for all three dimensions, making it the more useful unit when thickness and width vary between boards.
Board feet measures volume; square feet measures area. You cannot convert directly between them without knowing thickness — the same 12 square feet of material could be 6 board feet (at ½″ thick) or 24 board feet (at 2″ thick). Any board-feet-to-square-feet conversion has to go through thickness first.
1 cubic foot = 12 board feet
1 board foot = 1/12 cubic foot
Both are volume units, so converting between them is straightforward and exact — unlike the board-feet-to-square-feet case, no additional dimension is needed.
| Conversion | Value |
|---|---|
| 1 board foot | = 144 cubic inches (exact) |
| 1 board foot | = 1/12 cubic foot (exact) |
| 12 board feet | = 1 cubic foot (exact) |
| 1 board foot | ≈ 0.002360 cubic metres |
| 1 cubic metre | ≈ 423.8 board feet |
Nominal lumber sizes like "1×6" or "2×8" refer to rough-sawn dimensions before surfacing — the table below uses standard actual (surfaced) dimensions for common US dimensional lumber, all at 8 feet long:
| Nominal size | Actual size | Board feet (8ft length) |
|---|---|---|
| 1×6 | ¾″ × 5½″ | 2.750 bf |
| 1×8 | ¾″ × 7¼″ | 3.625 bf |
| 1×10 | ¾″ × 9¼″ | 4.625 bf |
| 1×12 | ¾″ × 11¼″ | 5.625 bf |
| 2×6 | 1½″ × 5½″ | 5.500 bf |
| 2×8 | 1½″ × 7¼″ | 7.250 bf |
| 2×10 | 1½″ × 9¼″ | 9.250 bf |
| 2×12 | 1½″ × 11¼″ | 11.250 bf |
These figures use standard actual (surfaced) dimensions, not the nominal 1×6 or 2×8 label directly — a true 2×6 measures 1½″ × 5½″, not a full 2″ × 6″. This calculator always uses whatever numbers you enter, actual or nominal, without assuming one or the other.
10% is a common starting point, not a universal figure. Appropriate waste depends on knots, checks, sapwood, grain selection, defects, board width variation, milling, jointer/planer loss, saw kerf, project layout, species and grade. A board-foot total also does not by itself tell you how many finished parts you can cut from a board — that depends on cutting layout, defect avoidance and saw kerf, not board footage alone.
BF = 1 × 8 × 10 ÷ 12 = 6.667 bf
BF per board = 1 × 6 × 8 ÷ 12 = 4.000 bf
Total = 4.000 × 10 = 40.000 bf
8/4 rough thickness treated as 2 inches:
BF = 2 × 10 × 8 ÷ 12 = 13.333 bf
Normalized to inches first: 25mm ≈ 0.984″, 200mm ≈ 7.874″, 2.4m ≈ 94.488″:
BF = 0.984 × 7.874 × 94.488 ÷ 144 = 5.085 bf
A board foot is a lumber volume equal to 144 cubic inches — equivalent to a board 1 inch thick, 12 inches wide and 12 inches long.
Multiply thickness in inches by width in inches by length in feet and divide by 12: BF = T(in) × W(in) × L(ft) ÷ 12. If length is in inches instead, divide by 144.
Board Feet = Thickness(in) × Width(in) × Length(ft) ÷ 12, or equivalently Thickness(in) × Width(in) × Length(in) ÷ 144 when length is measured in inches.
144 cubic inches exactly — the same volume as a 1 inch by 12 inch by 12 inch board.
Exactly 12 board feet per cubic foot, since a board foot is defined as 1/12 of a cubic foot.
For identical boards, multiply board feet per board by the quantity. For a project with different board sizes, use the cut-list mode to enter each size separately — the calculator sums every row into a project total.
It varies enormously by species, grade and supplier — enter your own price per board foot into this calculator for a project-specific estimate rather than relying on a general figure.
A pricing convention where lumber cost is quoted per board foot of volume, rather than per linear foot or per piece — common for hardwood, since it accounts for thickness and width as well as length.
Four-quarters, meaning 1 inch of rough-sawn thickness. Quarter notation describes thickness in quarter-inch units, unrelated to "quarter-sawn," which describes grain orientation.
Eight-quarters, meaning 2 inches of rough-sawn thickness. As with 4/4, the actual surfaced thickness after planing is typically somewhat less than the full rough figure.
No — board feet measures volume (thickness × width × length), while square feet measures area (width × length only). You can't convert between them without knowing thickness.
No — linear feet measures only length, ignoring thickness and width, while board feet accounts for all three dimensions. Two boards of the same length but different thickness or width have the same linear footage but different board footage.
Divide by 12 — 1 board foot equals exactly 1/12 of a cubic foot, since both are defined from the same 144-cubic-inch relationship.
Yes — this calculator lets thickness, width and length each use mm, cm or metres independently, converting internally to the inches the board foot formula is defined in, so you don't need to convert by hand.
Use actual measured dimensions for the most accurate result — nominal sizes like "2×6" don't match the true surfaced dimensions (1½″ × 5½″ for a real 2×6). This calculator uses exactly what you enter, without assuming either convention.
10% is a common starting point, but the right figure depends on knots, checks, sapwood, grain selection, defects, board width variation, milling losses, saw kerf, project layout, species and grade — there's no single correct percentage for every project.
No — they solve different problems. A board foot calculator (this page) works out lumber volume for pricing and ordering rough or dimensional timber. A board-and-batten calculator instead works out batten spacing and count for a wall treatment, which is really a linear-feet and layout question rather than a volume one — measure your wall width and divide by your chosen batten spacing to plan that layout.