Board Foot Calculator for Lumber and Logs
This board foot calculator works out how many board feet are in any piece of lumber or log, so you can estimate material needs and costs for woodworking and construction projects. A board foot (BF) is the standard North American unit for lumber volume: 1 inch thick × 12 inches wide × 12 inches long, or 144 cubic inches.
It has two calculation modes. Lumber mode uses the standard formula — thickness × width × length ÷ 144 — for sawn boards and dimensional lumber. Log (Doyle) mode estimates the usable board feet in a raw log using the Doyle scale, (Diameter − 4)² × Length ÷ 16.
How to Use the Board Foot Calculator
Pick a mode
Use Lumber (the default) for sawn boards, or switch to Log (Doyle) to estimate board feet from a raw log.
Enter the dimensions
In Lumber mode, choose a Preset Size or type your own thickness, width, and length — each field has its own unit selector (inches, feet, cm, mm). In Log mode, enter the small-end diameter (must be over 4 inches) and the log length.
Read the instant result
The board-foot total and the formula behind it update as you type. Set the Quantity if you have several identical pieces.
Build a material list
Click Add to List to save the current piece, then repeat for every item in your project. The list shows each entry's dimensions, quantity, and board feet with a running Total Board Feet.
Estimate the cost
Open the Cost Estimate section, enter a price per board foot, choose your currency, and adjust the waste percentage to see the subtotal, waste cost, and total.
Features
Lumber Board Feet
Calculate board feet for sawn lumber with the standard formula: thickness × width × length ÷ 144.
Doyle Log Scale
Estimate the board feet in a raw log from its small-end diameter and length using the widely used Doyle rule, (D − 4)² × L ÷ 16.
Preset Lumber Sizes
Pick from 12 common dimensions — 1×4, 1×6, 2×4, 2×6, 2×8, 2×10, 2×12, 4×4, 6×6 and more, all at the standard 8-foot length.
Per-Field Unit Conversion
Mix and match inches, feet, centimeters, and millimeters on each dimension — the calculator converts everything internally.
Quantity Multiplier
Set a quantity for identical pieces and the board-foot total scales automatically.
Material List
Add multiple lumber or log items to a project list and see the total board feet needed across every entry.
Cost Estimation
Enter a price per board foot and pick a currency to turn your total into a material cost.
Adjustable Waste Factor
Add a buffer for cuts, defects, and offcuts with a waste percentage from 0 to 50% (10% by default).
Saved Settings
Your material list, price, and waste settings are stored in your browser and restored when you return.
Frequently Asked Questions
What is a board foot?
A board foot is the standard unit for lumber volume in North America. One board foot is a piece of wood 1 inch thick, 12 inches wide, and 12 inches long — equal to 144 cubic inches.
How do you calculate board feet?
For lumber, multiply thickness (inches) × width (inches) × length (inches) and divide by 144. For example, a 2" × 6" × 8' board is 2 × 6 × 96 ÷ 144 = 8 board feet. This calculator does the math instantly and shows the formula it used.
How many board feet are in a 2×4×8?
A 2" × 4" × 8' board is 2 × 4 × 96 ÷ 144 = 5.33 board feet. Board-foot math in the lumber trade uses nominal dimensions, so a "2×4" counts as a full 2 by 4 even though the planed size is smaller.
What is the difference between board feet, linear feet, and square feet?
Board feet measure volume (thickness × width × length). Linear feet measure only length, regardless of thickness or width. Square feet measure flat area (width × length). Board feet are what you use to price lumber by volume.
How does the Doyle log scale work?
The Doyle rule estimates the usable lumber in a log using (Diameter − 4)² × Length ÷ 16, where the diameter is measured at the small end in inches and length is in feet. It tends to underestimate yield for small logs and is most accurate for logs 28 inches and larger.
What is a typical waste factor?
A waste factor of 10–15% is standard for most woodworking projects, covering saw kerf, defects, knots, and end trimming. For complex cuts or lower-grade lumber, consider 15–20%. The calculator defaults to 10% and lets you set anything from 0 to 50%.
What is the difference between nominal and actual lumber size?
Nominal sizes (like "2×4") refer to the rough-cut dimensions before planing. The actual size is smaller — a 2×4 is really 1.5" × 3.5". Board-foot calculations in the lumber industry typically use the nominal dimensions.
Is my data saved and private?
Yes. Your material list, price per board foot, and waste percentage are stored locally in your own browser and restored on your next visit. Nothing is sent to a server.
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