Lumber Calculator

Calculate board feet for lumber orders. Enter board thickness, width, length, and quantity to find total board feet, linear feet, and estimated cost. Ideal for woodworking, framing, and construction projects.

Board Feet Calculator

Board Feet Formula

Board Feet = (thickness_in × width_in × length_ft) / 12 Total BF = Board Feet per piece × quantity A "1 board foot" = 1 inch thick × 12 in wide × 12 in long (= 144 cubic inches)

Common Lumber Sizes

Nominal SizeActual SizeBF per 8-ft board
1×40.75" × 3.5"2.67
1×60.75" × 5.5"4.00
1×80.75" × 7.25"5.33
2×41.5" × 3.5"5.33
2×61.5" × 5.5"8.00
2×81.5" × 7.25"10.67

Frequently Asked Questions

What is a board foot?+
A board foot is a unit of volume for lumber equal to 144 cubic inches — the equivalent of a 1-inch thick, 12-inch wide, 12-inch long board. It's the standard unit for pricing hardwood and rough-sawn lumber.
Should I use nominal or actual dimensions?+
For board feet calculations, use nominal dimensions (the stated size like 2×4), not actual dimensions, as that's how lumber is sold and priced. For structural calculations and joinery, use actual dimensions.

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About the Lumber Calculator

This free lumber calculator helps you get accurate results instantly without needing to work through the math manually. Whether you need a quick estimate or a precise figure, having a reliable tool on hand saves time and reduces errors compared to manual calculation.

How to Use This Calculator

  1. Enter your values in the input fields above. Each field is labeled to guide you.
  2. Double-check your inputs — results are only as accurate as the numbers you enter.
  3. Click the Calculate button to see your result instantly.
  4. Use the result for your planning, budgeting, or decision-making.

Why Accurate Calculations Matter

Small errors in math calculations can compound into significant problems. A 1% miscalculation in a budget or measurement can translate to hundreds or thousands of dollars in wasted resources, or result in having to redo work entirely. This calculator uses the standard formulas and methods to give you reliable results you can trust.

Tips for Getting the Best Results

Frequently Asked Questions

Is this calculator free? Yes — completely free with no account, login, or payment required. Use it as many times as you need.

How accurate are the results? This calculator uses the standard formulas for lumber calculations. Results are accurate for typical use cases. For specialized or high-stakes applications, consult a professional.

Does it work on mobile? Yes. This calculator is fully responsive and works on smartphones, tablets, and desktops.