Lumber Calculator

Enter your lumber's Thickness, Width, Length, and Quantity into the Lumber Calculator to get the Board Feet per Piece, Total Board Feet, and Total Cubic Feet — then add a Price per Board Foot to see your Total Cost before you ever set foot in the lumber yard.

inches

Lumber thickness in inches (e.g., 1 for 4/4 lumber, 1.5 for 6/4 lumber)

inches
feet
pieces

Cost per board foot of lumber

Results

Board Feet per Piece

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Total Board Feet

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Total Cost

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Total Cubic Feet

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Cost Breakdown

Frequently Asked Questions

What is a board foot and how is it calculated?

A board foot is a unit of volume for lumber equal to one square foot that is one inch thick (144 cubic inches). It's calculated using the formula: Board Feet = Length (ft) × Width (in) × Thickness (in) ÷ 12.

How do I convert lumber thickness to decimal inches?

Lumber is often sold in quarters: 4/4 = 1 inch, 5/4 = 1.25 inches, 6/4 = 1.5 inches, 8/4 = 2 inches. These refer to rough dimensions before surfacing.

What's the difference between hardwood and softwood pricing?

Hardwood lumber is typically more expensive and sold by board foot, while softwood is often sold by linear foot. Hardwoods range from $3-20+ per board foot, while softwoods are usually $1-5 per board foot.

How much lumber waste should I account for in my project?

Plan for 10-15% extra lumber to account for cuts, mistakes, and defects. For complex projects with many cuts, consider adding 20% to your calculated quantity.

Can I use this calculator for pressure-treated lumber?

Yes, this calculator works for all lumber types. Pressure-treated lumber follows the same board foot calculations, though pricing is typically higher than regular softwood.

What's the difference between nominal and actual lumber dimensions?

Nominal dimensions are the rough-cut size (like 2×4), while actual dimensions are smaller after drying and planing (1.5×3.5 for a 2×4). This calculator uses actual dimensions for accuracy.

How do I calculate studs needed for framing a wall?

For wall framing, studs are typically spaced 16 or 24 inches on center. Divide wall length by stud spacing, add 1, then add extra studs for corners, doors, and windows.

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