Lumber Calculator
Calculate the total board feet and cost of lumber for framing and construction projects.
This free online lumber calculator provides instant results with no signup required. All calculations run directly in your browser — your data is never sent to a server. Enter your values below and see results update in real time as you type. Perfect for everyday calculations, homework, or professional use.
How many boards you need
Minimum: 0
Nominal thickness (e.g., 2 for a 2x)
Minimum: 0
Nominal width (e.g., 6 for a 2x6)
Minimum: 0
Length of each piece
Cost per board foot
Results
BF per Piece
8 BF
Total Board Feet
80 BF
Total Cost
$400.00
How to Use This Calculator
Enter your input values
Fill in all required input fields for the Lumber Calculator. Most fields include unit selectors so you can work in your preferred unit system — metric or imperial, whichever matches your problem.
Review your inputs
Double-check that all values are correct and that you have selected the right units for each field. Incorrect units are the most common source of calculation errors and can produce results that are off by factors of 2, 10, or more.
Read the results
The Lumber Calculator instantly computes the output and displays results with units clearly labeled. All calculations happen in your browser — no loading time and no data sent to a server.
Explore parameter sensitivity
Try adjusting individual input values to see how the output changes. This is a quick and effective way to develop intuition about how different parameters influence the result and to identify which inputs have the largest effect.
Formula Reference
Lumber Calculator Formula
See calculator inputs for the governing equation
Variables: All variables and their units are labeled in the calculator interface above. Input fields accept values in multiple unit systems — select your preferred unit from the dropdown next to each field.
When to Use This Calculator
- •Use the Lumber Calculator when you need accurate results quickly without the risk of manual computation errors or unit conversion mistakes.
- •Use it to verify calculations made by hand or in spreadsheets — an independent check can catch errors before they lead to costly decisions.
- •Use it to explore how changing input parameters affects the output — a quick way to develop intuition and identify the most influential variables.
- •Use it when collaborating with others to ensure everyone is working from the same numbers and applying the same assumptions.
About This Calculator
The Lumber Calculator is a free, browser-based calculation tool for engineers, students, and technical professionals. Calculate the total board feet and cost of lumber for framing and construction projects. It implements standard formulas and supports both metric (SI) and imperial unit systems with automatic unit conversion. All calculations are performed instantly in your browser with no data sent to a server. Use this calculator as a quick reference and sanity-check tool during design, analysis, and learning. Always verify results against primary engineering references and applicable standards for any safety-critical application.
About Lumber Calculator
Lumber is the backbone of wood-frame construction, and board feet is the standard unit for buying and selling hardwood and dimensional lumber. One board foot equals a piece of wood 1 inch thick, 12 inches wide, and 1 foot long (144 cubic inches). This calculator determines the board footage for your project based on the number of pieces, their dimensions, and price per board foot. Whether you are framing walls, building a deck, or ordering hardwood for furniture, understanding board feet ensures accurate cost estimates and prevents ordering errors.
The Math Behind It
Formula Reference
Board Feet
BF = Thickness(in) x Width(in) x Length(ft) / 12
Variables: Nominal dimensions; 1 board foot = 144 cubic inches
Worked Examples
Example 1: Ten 2x6 boards, 12 feet long
Pieces = 10, Thickness = 2 in, Width = 6 in, Length = 12 ft, Price = $5/BF
You need 120 board feet of 2x6, costing $600.
Common Mistakes & Tips
- !Using actual dimensions instead of nominal dimensions for dimensional lumber board foot calculations.
- !Confusing linear feet with board feet -- they are different units.
- !Not adding waste factor for defects, miscuts, and unusable short pieces.
- !Forgetting that lumber prices vary significantly by species and grade.
Related Concepts
Used in These Calculators
Calculators that build on or apply the concepts from this page:
Frequently Asked Questions
What is a board foot?
A board foot is a unit of volume equal to 144 cubic inches -- equivalent to a piece of wood 1 inch thick, 12 inches wide, and 1 foot long. It is the standard unit for buying and selling lumber.
Why are nominal and actual lumber dimensions different?
Nominal dimensions (2x4, 2x6, etc.) refer to the rough-sawn size before the lumber is dried and planed smooth. The planning process removes about 1/2 inch from each dimension, so a nominal 2x4 is actually 1.5 x 3.5 inches.