🪵 Board Foot Calculator
Find the board feet and cost of any hardwood lumber order from the thickness, width, and length. Get board feet, cubic feet, weight, and price — instantly. Free, no sign-up. Oak, walnut, maple & pine.
A board foot calculator tells you how much lumber is in a board or an order, and what it will cost. A board foot is the standard unit for hardwood — 144 cubic inches of wood, the amount in a board 1 foot long, 1 foot wide, and 1 inch thick. The formula is:
How to calculate board feet in 3 steps:
- Pick the board thickness — 4/4 is 1 inch, 8/4 is 2 inches — and enter the width and length.
- Pick a wood species and waste factor — red oak and 10% waste are the standard defaults.
- Click Calculate Board Feet to see total board feet, weight, and estimated lumber cost instantly.
For example, ten boards 1 inch thick, 6 inches wide, and 8 feet long hold (1 × 6 × 8) ÷ 12 = 4 board feet each, or 40 board feet total. As red oak that's about 152 pounds of lumber.
Board Foot Calculator
Pick a thickness, enter width and length, see board feet, weight and cost instantly.
Know Exactly How Much Lumber You Need –
and What It Will Cost by the Board Foot
Hardwood is sold by the board foot — a volume unit, not a length — and the math trips up first-time buyers. This free calculator turns thickness, width, and length into board feet, weight, and cost in seconds, so you order the right amount of oak, walnut, or maple.
⚡ Try the Calculator NowThe Board Foot: How Hardwood Is Measured and Sold
Walk into a hardwood dealer and the price is not per board or per foot of length — it is per board foot. For anyone used to buying dimensional lumber by the piece, that first hardwood order can be confusing. The board foot is a volume unit, and understanding it is the difference between a confident purchase and an expensive guess.
One board foot is 144 cubic inches of wood — the amount in a plank 1 foot long, 1 foot wide, and 1 inch thick. Because it measures volume, a thick narrow board and a thin wide one can hold the same board footage. That is exactly why hardwood, which comes in random widths and lengths, is sold this way: it is the only fair measure of how much wood you are actually buying.
This free Board Foot Calculator does the conversion for you. Pick a thickness, enter the width, length, and number of boards, choose a wood species, and it returns total board feet, cubic feet, weight, and an estimated cost — so you walk into the lumberyard knowing exactly what to ask for.
How the Board Foot Calculator Works
Pick a thickness, enter three numbers, choose a species, and click once. The calculator returns board feet, weight, and cost. Here is what each field does.
Pick the Board Thickness
Choose 4/4, 5/4, 6/4, or 8/4 — the standard hardwood thicknesses. The tab sets the thickness in inches; you can override it for any non-standard board.
Choose Feet or Inches
Toggle whether the board length is measured in feet or inches. Long boards are usually given in feet; short offcuts and project parts in inches.
📐 Thickness and width are always entered in inches.Enter Width & Length
Enter the board's width in inches and its length. Use the rough-sawn dimensions — the size the dealer measures and charges for, before any planing.
📊 A 1×6 board is 1 inch thick and 6 inches wide.Enter the Number of Boards
Buying several identical boards? Enter the count and the calculator totals the board feet. For boards of different sizes, run each size separately.
Pick Species & Waste
Wood species sets the auto-filled price per board foot and the weight. Waste factor adds margin for knots, defects, and saw cuts — 10% is standard.
Hit Calculate — Read Every Number
Instantly see total board feet, cubic feet, cubic inches, linear feet, weight, the order size with waste, and the estimated lumber cost.
✅ Formula: BF = (Thickness × Width × Length ft) ÷ 12The Board Foot Formula, Explained
There is one formula, and it has two forms depending on whether the length is in feet or inches. Both describe the same thing: the volume of wood, in units of 144 cubic inches.
The core idea: One board foot is 144 cubic inches — a piece 12 inches long, 12 inches wide, and 1 inch thick. To find the board feet in any board, calculate its volume in cubic inches and divide by 144.
Length in feet: When the length is measured in feet, the formula simplifies to board feet = (thickness in inches × width in inches × length in feet) ÷ 12. The 12 in the denominator comes from converting feet to inches and dividing by 144 — the two steps collapse into one. A board 1 inch thick, 6 inches wide, and 8 feet long is 1 × 6 × 8 ÷ 12 = 4 board feet.
Length in inches: When the length is in inches, divide by 144 instead: board feet = (thickness × width × length, all in inches) ÷ 144. This is the more literal form — total cubic inches divided by the 144 cubic inches in a board foot. The same 8-foot board, measured as 96 inches, gives 1 × 6 × 96 ÷ 144 = 4 board feet. Same answer.
Multiple boards: Calculate one board, then multiply by the quantity. Ten identical 4-board-foot planks total 40 board feet. If your boards are different sizes, calculate each size and add the results — the calculator's quantity field handles identical boards in one step.
Thickness, Size & Weight Tables
A few reference numbers cover most lumber planning — the quarter-inch thickness system and the board-foot weight of common species are the ones worth knowing.
| Quarter Notation | Rough Thickness | Typical Use |
|---|---|---|
| 4/4 | 1 inch | Tabletops, panels, general furniture |
| 5/4 | 1¼ inch | Stair treads, thick shelving |
| 6/4 | 1½ inch | Frames, rails, sturdy components |
| 8/4 | 2 inch | Table legs, heavy structural parts |
The formula in plain language: Multiply thickness by width by length, keeping thickness and width in inches. If the length is in feet, divide by 12; if in inches, divide by 144. A 1 × 6 board 8 feet long is (1 × 6 × 8) ÷ 12 = 4 board feet.
Board Feet of Common Board Sizes
| Board (rough) | Per Foot of Length | For an 8-ft Board |
|---|---|---|
| 1″ × 4″ (4/4) | 0.33 BF | 2.67 BF |
| 1″ × 6″ (4/4) | 0.50 BF | 4.00 BF |
| 1″ × 8″ (4/4) | 0.67 BF | 5.33 BF |
| 1″ × 12″ (4/4) | 1.00 BF | 8.00 BF |
| 2″ × 8″ (8/4) | 1.33 BF | 10.67 BF |
Approximate Weight Per Board Foot
| Species | Weight Per BF | Character |
|---|---|---|
| Pine | ~2.3 lb | Light softwood, easy to work |
| Poplar | ~2.5 lb | Light hardwood, takes paint well |
| Walnut | ~3.2 lb | Medium weight, rich dark color |
| Hard maple | ~3.7 lb | Dense, pale, very hard-wearing |
| Red oak | ~3.8 lb | Dense, strong, open grain |
These weights are for kiln-dried lumber. Green or freshly milled wood holds far more water and can weigh half again as much, which matters when you are loading a vehicle.
Factors That Affect Your Lumber Order
The formula gives a clean number from clean inputs. A real lumber order has a few wrinkles worth planning for.
Wood Species Compared: Cost, Weight & Use
Species drives both the price per board foot and the character of the finished piece. Here is how the common choices compare.
| Species | Price/BF | Best For | Watch Out For |
|---|---|---|---|
| Pine | $2–$4 | Shelving, rustic builds, practice pieces | Soft — dents easily, knots are common |
| Poplar | $3–$5 | Painted furniture, drawer boxes, trim | Green streaks — not ideal for clear finish |
| Red oak | $5–$9 | Furniture, cabinets, flooring, trim | Open grain shows through thin finishes |
| Hard maple | $6–$10 | Cutting boards, tabletops, hard-use pieces | Dense and hard — tough on tools |
| Walnut | $12–$20 | Heirloom furniture, accents, fine detail | Expensive — buy carefully, waste little |
How to Buy Hardwood Lumber: A Phase-by-Phase Roadmap
A good lumber purchase starts long before the lumberyard. Here are the four phases from project plan to loaded vehicle.
Write down each component with its thickness, width, and length. Group parts by thickness, since lumber is bought by thickness. This cut list is the foundation of an accurate board-foot estimate.
Run the board feet for each thickness group and total them. Add a 10–15% waste factor for knots, defects, and cutting loss. The result is the board-foot figure to take to the dealer.
Pick a species for appearance, hardness, and cost, and a grade for how much clear wood you need. A higher grade costs more per board foot but wastes less — sometimes the better value for a visible project.
At the lumberyard, sight down each board for cup, bow, and twist, and look for the grain and color you want. Hardwood is sold rough — picture the finished part inside the rough board before you buy it.
2026 Hardwood Lumber Cost Breakdown
Lumber cost is the board feet multiplied by the price per board foot — but the species and grade you choose swing that price widely.
The calculator's cost estimate uses a typical 2026 price per board foot for the species you select. Real prices depend on grade, thickness, region, and dealer. Thicker stock (8/4 and up) and wider boards usually carry a premium over standard 4/4.
| Project | Approx. Board Feet | In Red Oak | In Walnut |
|---|---|---|---|
| Small bookshelf | ~25 BF | $140–$250 | $330–$550 |
| Coffee table | ~35 BF | $190–$350 | $460–$770 |
| Dining table | ~70 BF | $390–$700 | $920–$1,540 |
| Set of 4 chairs | ~50 BF | $280–$500 | $660–$1,100 |
| Kitchen cabinets (run) | ~200 BF | $1,100–$2,000 | $2,600–$4,400 |
Example Board Foot Calculations
Three lumber orders, three species — all worked through with verified math so you can sanity-check your own. Each assumes a 10% waste factor.
How to Save Money on a Lumber Order
Hardwood is expensive, and small choices add up across a board-foot order. These six habits keep the bill down without hurting the project.
The biggest lever is buying the right grade, not the highest. A top grade yields more clear wood but costs more per board foot; a lower grade is cheaper but wastes more. For hidden parts — drawer sides, shelf backs, internal frames — a lower grade is the smart, cheaper choice. Save the premium grade for the surfaces that show.
The second lever is an efficient cut list. Boards bought to fit your parts with minimal offcuts stretch every board foot. Planning long parts from long boards, and nesting small parts into the gaps, can cut the waste factor — and the order — by several percent.
Six Cost-Cutting Moves
When This Calculator Is the Wrong Tool
The board foot formula is exact, but a lumber order has realities a calculator cannot see. Here is where the output needs judgment.
1. Construction lumber sold by the piece. Dimensional softwood — 2×4s, studs, framing — is sold per piece at nominal sizes, not by the board foot. This calculator is built for hardwood sold by volume; for a framing material list, count pieces instead.
2. The waste factor is an estimate. How much wood you actually lose depends on the lumber grade, your cutting layout, and how much grain matching the project needs. The 10–15% default is a guide, not a guarantee — a knotty board or a figured-wood project can need much more.
3. Rough vs surfaced confusion. The calculator does not know whether you entered rough or surfaced dimensions. Board feet are billed on the rough size; enter the surfaced size and you will under-estimate what the dealer charges. Always use the rough numbers.
4. Sheet goods and turning blanks. Plywood and other sheet goods are sold by the sheet, and turning blanks or specialty cuts are priced individually. The board foot is for solid lumber sold by volume — other wood products use their own units.
Where to go instead: For the surface area of a project — flooring, paneling, sheet coverage — a square footage calculator is the right tool. For bulk volume in cubic feet or yards, a cubic feet calculator handles it. This tool's strength is solid hardwood priced by the board foot.
Lumber Terms You'll See On This Page
Quick reference for the lumber terms used throughout this calculator.
- Board Foot
- The standard unit for hardwood lumber volume — 144 cubic inches, the amount of wood in a board 1 ft long, 1 ft wide, and 1 inch thick.
- Quarter Notation
- The way hardwood thickness is quoted, in quarter-inches. 4/4 is 1 inch, 5/4 is 1.25 inches, 6/4 is 1.5 inches, 8/4 is 2 inches.
- Rough-Sawn
- Lumber as it comes from the sawmill, before planing. Board feet are figured and billed on rough-sawn dimensions.
- Surfaced (S2S, S4S)
- Lumber planed smooth — on two sides (S2S) or all four (S4S). Surfaced wood is thinner than its rough size but billed as the rough size.
- Linear Foot
- A measure of length only — one foot along a board — ignoring thickness and width. Used for trim and softwood, not hardwood.
- Hardwood
- Wood from broadleaf trees — oak, maple, walnut, poplar. Usually denser and sold by the board foot.
- Softwood
- Wood from coniferous trees such as pine. Lighter and cheaper, often sold by the piece or linear foot.
- Grade
- A quality rating for lumber based on the amount of clear, defect-free wood. Higher grades cost more and waste less.
- FAS
- "Firsts and Seconds" — a top hardwood grade with long, wide clear sections, used where appearance matters.
- Kiln-Dried
- Lumber dried in a kiln to a low, stable moisture content, ready for indoor furniture work.
- Cut List
- A list of every part a project needs, with thickness, width, and length — the basis of an accurate lumber order.
- Waste Factor
- A percentage added to the calculated board feet to cover knots, defects, and saw cuts. Ten percent is the standard default.
- Resaw
- Cutting a thick board into thinner pieces along its width — a way to get thin stock from cheaper thick boards.
- Kerf
- The width of material removed by a saw blade in a cut. It is a small but real source of waste across many cuts.
Frequently Asked Questions
The most common questions about calculating and buying lumber by the board foot.
What is a board foot?
A board foot is the standard unit for measuring hardwood lumber volume. One board foot equals 144 cubic inches of wood — the amount in a board 1 foot long, 1 foot wide, and 1 inch thick. It is a volume measure, so a 1-inch board 12 inches wide and 1 foot long, and a 2-inch board 6 inches wide and 1 foot long, are both exactly one board foot.
How do I calculate board feet?
Multiply the thickness in inches by the width in inches by the length in feet, then divide by 12. A board 1 inch thick, 6 inches wide, and 8 feet long is 1 × 6 × 8 ÷ 12 = 4 board feet. If the length is in inches instead, multiply thickness by width by length and divide by 144. Multiply by the number of boards for the total.
What is the board foot formula?
The formula is board feet = (thickness in inches × width in inches × length in feet) ÷ 12. When the length is measured in inches, the formula is (thickness × width × length) ÷ 144, since one board foot is 144 cubic inches. Both give the same result — they just expect the length in different units.
What does 4/4 lumber mean?
Hardwood thickness is quoted in quarter-inches, so 4/4 (“four-quarter”) means 1 inch thick, 5/4 means 1.25 inches, 6/4 means 1.5 inches, and 8/4 means 2 inches. These figures describe rough-sawn lumber; once the board is planed smooth, the finished thickness is a little less — a 4/4 board often finishes around 13/16 inch.
How is lumber priced by the board foot?
Hardwood lumber is sold by the board foot, so the total price is the board feet multiplied by the price per board foot. In 2026, pine runs about $3 per board foot, red oak around $7, hard maple around $8, and walnut $12 or more. Thicker and wider boards contain more board feet, so they cost more even at the same per-board-foot price.
What is the difference between a board foot and a linear foot?
A linear foot measures only length — one foot along the board, regardless of its thickness or width. A board foot measures volume, accounting for thickness and width as well. Softwood and trim are often sold by the linear foot, while hardwood is sold by the board foot, because volume reflects the actual amount of wood.
How much does a board foot of lumber weigh?
The weight of a board foot depends on the wood species and its moisture content. Dry pine is roughly 2 to 2.5 pounds per board foot, while dense hardwoods like oak and maple are closer to 3.5 to 4.5 pounds. Green or freshly cut lumber weighs considerably more than kiln-dried lumber of the same species.
How much waste should I add for a lumber project?
A 10% to 15% waste allowance is standard for a hardwood project. Add 10% for straightforward work, and 15% or more when the boards have knots or defects, when you are cutting many short pieces, or when grain matching matters. Lumber is graded, and even good boards have sections you will cut away, so ordering extra avoids running short.
How do I calculate board feet for multiple boards?
Calculate the board feet of one board — thickness times width times length, divided by 12 — then multiply by the number of identical boards. For ten boards that are each 4 board feet, the total is 40 board feet. If your boards are different sizes, calculate each size separately and add the results.
Is a board foot the same as a square foot?
No. A square foot measures area — length times width — and ignores thickness. A board foot measures volume and includes thickness. A board that is 1 inch thick and covers 12 square feet of surface contains 12 board feet, but a 2-inch board covering the same 12 square feet contains 24 board feet.
How do I figure board feet from a rough-cut board?
Hardwood board feet are figured from the rough-sawn dimensions — the thickness and width before the board is planed and the size you are charged for. Measure the board as it comes from the mill, in its rough state, and use those numbers in the formula. The finished, planed dimensions are smaller and would understate what you paid for.
Why is hardwood sold by the board foot instead of by the piece?
Hardwood boards come in random widths and lengths straight from the log, so selling by the piece would be unfair — boards vary too much. The board foot measures the actual volume of wood in each board, so a wide, long, thick board costs proportionally more than a small one. It gives buyer and seller a consistent, volume-based price.
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