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Board Foot Calculator

Calculate total board feet for a piece or quantity of lumber from thickness, width, and length, with an optional price-per-board-foot cost estimate.

Author: Naeem Ullah
•Last Updated: September 17, 2026•
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Active Calculation FormulaBoard Feet = (Thickness × Width × Length) ÷ 12

Adjust Variables

in
thickness
Min: 0 inMax: 4 in
in
width
Min: 0 inMax: 12 in
ft
length
Min: 1 ftMax: 100 ft
pieces
quantity
Min: 1 piecesMax: 10k
Use Real Campaign Presets
Real-Time Results
Board Feet per Piece0
Total Board Feet0
All calculations are compiled with double-precision floating math directly in this browser frame. Perfect precision guaranteed.

Interactive Step-by-Step Calculation Proofs

View how variables resolve algebraically down to peer-reviewed standard outputs.

Why Use This Calculator

Board feet is the standard unit lumber yards use to price hardwood and specialty lumber, and it measures volume rather than a single dimension — a 2×6 and a 1×12 can contain the same board footage. The formula is Board Feet = Thickness (in) × Width (in) × Length (ft) ÷ 12, or equivalently Thickness (in) × Width (in) × Length (in) ÷ 144. Lumber is commonly sold and labeled by its nominal size (e.g. "2×6"), which is the size before drying and planing — the actual finished dimensions are smaller (a nominal 2×6 is actually 1.5" × 5.5"). This calculator lets you enter either nominal or actual dimensions directly, so measure the real board in front of you rather than guessing which convention applies. Add a price per board foot to get an instant total material cost for your order.

Mathematical Formula Explanation

Calculated standard benchmarks are based on direct functional dependencies. The primary calculation logic follows this formula:

Board Feet = Thickness (in) × Width (in) × Length (ft) ÷ 12

One board foot is the volume of a board 1 inch thick, 12 inches wide, and 1 foot long (144 cubic inches). The formula multiplies thickness and width in inches by length in feet, then divides by 12 to convert. Total Board Feet for a Project scales that single-piece result by quantity and adds an optional cost, using whichever length unit — feet or inches — is more convenient to measure with.

Worked Examples (Step-by-Step)

These examples show board feet for a single piece of lumber and total board feet and cost for a multi-piece order.

Case Scenario 1

Example 1: Board Feet for a Single 2×6

“A woodworker has one actual 2" × 6" board that is 8 feet long. How many board feet is that?”

Given Inputs
  • THICKNESS: 2
  • WIDTH: 6
  • LENGTH: 8
  • QUANTITY: 1
Computed Outputs
  • BFPERPIECE: 8
  • TOTALBF: 8
Case Scenario 2

Example 2: Total Cost for a Multi-Board Order

“A builder needs 20 boards, each 1" thick, 8" wide, and 10 feet long, at $6 per board foot. What is the total board footage and cost?”

Given Inputs
  • THICKNESS: 1
  • WIDTH: 8
  • LENGTH: 10
  • QUANTITY: 20
  • PRICEPERBF: 6
Computed Outputs
  • TOTALBF: 133.33
  • TOTALCOST: 800
Case Scenario 3

Example 3: Board Feet Using Nominal 2×8 Dimensions

“A DIYer measures a nominal '2×8' board and finds its actual size is 1.5" × 7.25", 12 feet long. How many board feet is it, entering the actual measured size?”

Given Inputs
  • THICKNESS: 1.5
  • WIDTH: 7.25
  • LENGTH: 12
  • QUANTITY: 1
Computed Outputs
  • BFPERPIECE: 10.88
  • TOTALBF: 10.88

Frequently Asked Questions (FAQ)

Board Feet = Thickness (in) × Width (in) × Length (ft) ÷ 12. For example, a board 2 inches thick, 6 inches wide, and 8 feet long has 2 × 6 × 8 ÷ 12 = 8 board feet. If your length is measured in inches instead of feet, use Board Feet = Thickness (in) × Width (in) × Length (in) ÷ 144.

A board foot is a unit of lumber volume equal to a board 1 inch thick, 12 inches wide, and 1 foot long — 144 cubic inches. It's the standard unit for pricing hardwood, specialty, and rough-sawn lumber, since it accounts for thickness as well as width and length, unlike linear footage which ignores thickness.

Nominal size is the label lumber is sold under (e.g. "2×6"), based on its dimensions before kiln drying and planing. Actual size is the true finished dimension after milling, which is smaller — a nominal 2×6 is actually 1.5" × 5.5", and a nominal 2×4 is actually 1.5" × 3.5". This calculator accepts whichever dimensions you enter, so measure the physical board with a tape measure and enter the actual size for the most accurate board footage.

Using actual dimensions (1.5" × 3.5") for a nominal 2×4 that is 8 feet long: 1.5 × 3.5 × 8 ÷ 12 = 3.5 board feet. Using nominal dimensions (2" × 4") instead gives 2 × 4 × 8 ÷ 12 = 5.33 board feet — this is why it matters which size convention you use, and why lumber yards typically price by nominal size even though actual milled size is smaller.

Softwood construction lumber (pine, spruce, fir) typically runs $2–$6 per board foot depending on grade and market conditions. Common hardwoods like oak or maple run $5–$12 per board foot, while premium or exotic hardwoods (walnut, cherry, exotic species) can run $12–$30+ per board foot. Prices fluctuate significantly with lumber market conditions, so check current pricing with your supplier.

Calculate the board feet for one piece, then multiply by the quantity: Total Board Feet = (Thickness × Width × Length ÷ 12) × Quantity. For example, 20 boards each measuring 1" × 8" × 10 ft have (1 × 8 × 10 ÷ 12) × 20 = 133.33 total board feet. Multiply by your price per board foot to get total material cost.

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