Board Footage Calculator

Calculate lumber volume in board feet for woodworking projects

100% FreeEasy to UseWoodworking

Required Inputs

Enter thickness, width, length and quantity

Thickness (in)

Examples: $4/4 = 1 \text{ in}$ , $8/4 = 2 \text{ in}$ , decimals allowed

Width (in)

Ex: 8 1/4 or 8.25

Length

Ex: $8 \text{ ft} = 96 \text{ in}$

Quantity

What is a Board Foot?

A board foot equals 144 cubic inches of lumber, representing the standard unit for measuring lumber volume used by woodworkers, carpenters, and lumber suppliers worldwide.

1 \text{ board foot} = 1 \text{ in} \times 12 \text{ in} \times 12 \text{ in} = 144 \text{ in}^3

Why Board Feet?

✓Industry Standard: Universal measurement system used by lumberyards and suppliers
✓Pricing: Lumber is typically sold by board feet, making cost estimation easier
✓Planning: Helps woodworkers calculate material needs for projects accurately

Lumber Thickness Guide

Quarter System Nomenclature

Lumber thickness is commonly expressed in quarters of an inch, where each quarter equals 0.25 inches:

4/4 = 1 \text{ in}

(1 inch)

5/4 = 1.25 \text{ in}

(1¼ inch)

6/4 = 1.5 \text{ in}

(1½ inch)

8/4 = 2 \text{ in}

(2 inches)

Note: Our calculator accepts both fractional formats (4/4) and decimal values (1.0).

Common Lumber Sizes

1×4: Actually 0.75" × 3.5" (nominal vs. actual dimensions)

2×4: Actually 1.5" × 3.5" (most common framing lumber)

2×6: Actually 1.5" × 5.5" (wider framing option)

Measuring Tips & Best Practices

1Thickness Measurement

Measure at the thickest point of the board
Account for rough-sawn vs. planed dimensions
Use actual thickness, not nominal size

2Width & Length

For irregular widths, use average width
Round lengths to the nearest inch for estimation
Measure in inches for consistency

Calculation Formula

\text{Board Feet} = \frac{\text{Thickness (in)} \times \text{Width (in)} \times \text{Length (in)}}{144}

This formula converts cubic inches to board feet by dividing by 144 (12 × 12).

Authoritative Lumber Resources

Woodworkers Guild

Comprehensive guide to understanding and calculating board feet

Wood Magazine

Lumber calculator and woodworking project planning tools

NHLA Grading Rules

National Hardwood Lumber Association official grading standards

Frequently Asked Questions

What is a board foot?

A unit of lumber volume equal to 144 in³, or a board 1 in thick × 12 in wide × 12 in long. Standard pricing unit for hardwood.

How do I calculate board feet?

BF = (T_in × W_in × L_in) / 144. Or: BF = (T_in × W_in × L_ft) / 12. Example: 1 × 6 × 8 ft = (1 × 6 × 8) / 12 = 4 BF.

What does 4/4, 5/4, etc. mean?

Fractional quartersawn notation: 4/4 = 1 in, 5/4 = 1.25 in, 6/4 = 1.5 in, 8/4 = 2 in thick rough lumber. Finished thickness is typically 1/8-1/4 in less.

How is board foot different from linear foot?

Linear foot measures only length. Board foot accounts for thickness and width, so it better reflects how much wood you're getting for the price.

Does board foot apply to plywood?

Plywood is usually sold by the sheet (typically 4×8 ft) or by square foot of coverage, not by board foot. Board foot is the standard for rough / dimensional hardwood lumber.

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