Board Foot Calculator: Lumber Volume & Cost

Calculate lumber volume in board feet for up to four lots of rectangular boards. Enter thickness, width, length, and piece count. Add an optional shared price per board foot to estimate lumber cost.

Lumber dimensions, quantity, and cost

Measurement units

Lot 1

Thickness (in)Width (in)Length (ft)Number of pieces (whole number)

Lot 2 (optional)

Thickness (in)Width (in)Length (ft)Number of pieces (whole number)

Lot 3 (optional)

Thickness (in)Width (in)Length (ft)Number of pieces (whole number)

Lot 4 (optional)

Thickness (in)Width (in)Length (ft)Number of pieces (whole number)

Price per board foot ($, optional)

Leave all numeric fields in unused lots blank. All lots use the same optional price per board foot. Calculate products with different rates separately. Dimensions accept up to 4 decimal places; price accepts 2; quantities must be whole numbers.

Choose the dimensions that match your purpose. For geometric volume, use actual rectangular measurements. For a purchase estimate, confirm the supplier's billing dimensions and tally rules. The calculator does not convert nominal sizes to actual sizes or infer dressed lumber dimensions.

Use decimal dimensions, not fractions: 1/2 inch = 0.5 inch, and 8 ft 6 in = 8.5 ft. A 4/4 stock designation is not a decimal input or a guarantee of finished thickness; confirm what measurement the supplier bills. Changing units clears dimensions while retaining quantities and price.

Enable JavaScript to calculate. With thickness and width in inches and length in feet, board feet = thickness x width x length x quantity / 12. Add all lots before applying the price per board foot. One board foot equals 144 cubic inches.

How do I calculate board feet of lumber?

A board foot is a volume equal to 144 cubic inches: a piece 1 inch thick, 12 inches wide, and 12 inches long. With length entered in feet, divide thickness x width x length by 12, then multiply by the number of pieces. Add separate lots to obtain the total.

Worked example

Ten boards measured at 1 inch thick, 6 inches wide, and 8 feet long contain 4 board feet each, or 40 board feet total. Add five boards measured at 2 inches thick, 8 inches wide, and 10 feet long: each contains 13.3333 board feet, or 66.6667 board feet for that lot. Combined volume is 106.6667 board feet. At an illustrative $5 per board foot, cost rounded once is $533.33. The measurements and price are examples, not nominal-size conversions or current market prices.

Board feet versus square feet and linear feet

Square feet measure area and require a thickness to determine board feet. Linear feet measure length and require both width and thickness. At 1 inch thickness, 1 square foot contains 1 board foot; at 2 inches thickness, it contains 2 board feet. A volume result does not specify how many usable lengths a cutting plan requires.

Nominal sizes and supplier billing

A nominal stock name does not necessarily describe the actual finished cross-section. Hardwood tally and billing measurements can also differ from a measurement of the finished board. Enter the appropriate documented dimensions for the calculation you want. Confirm supplier pricing and rounding rather than assuming a universal nominal-to-actual conversion.

Can I estimate board feet from a log?

No. A round log or standing tree does not yield its entire geometric volume as usable rectangular lumber. Log-scale rules and sawmill yield methods account for different assumptions. This calculator is for specified rectangular board dimensions, not a log, tree, or sawmill recovery estimate.

What does the cost include?

Only calculated board feet multiplied by the shared rate you enter. It does not include delivery, tax, milling, finishing, defects, or material needed to complete a cutting list. Plan purchases separately and check any supplier minimum or tally convention before ordering.

Board foot calculation guide

How to calculate board feet of lumber and cost, including unit conversions, multiple lots, and supplier billing dimensions.