Construction glossary · Units of measure
What is BF (board foot) in construction?
A board foot (bf) is the lumber volume unit equal to a piece 1 inch thick, 12 inches wide, and 1 foot long, which is 144 cubic inches. The formula is nominal thickness in inches times nominal width in inches times length in feet, divided by 12. Framing packages and timbers are often priced per thousand board feet, written MBF.
Updated June 2026 · Reviewed by the Ruh construction team
What a board foot fills
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Book a walkthroughBoard feet appear on lumber quotes, framing bids, and supplier price sheets, especially for dimensional lumber and timbers bought in volume. Mills and yards quote commodity framing lumber per MBF, and the futures market that drives those quotes is also stated per MBF, so an estimator who can move between sticks of lumber and board feet can sanity check a framing package against the market. The critical convention: board feet use NOMINAL dimensions, so a 2x10 counts as 2 inches by 10 inches even though its actual dressed size is 1.5 by 9.25 inches. New estimators make three common mistakes: computing bf from actual rather than nominal sizes, applying board feet to sheet goods (plywood and OSB are taken off in square feet or sheet count, never bf), and forgetting that engineered lumber like LVL is typically priced per linear foot, not per board foot.
Count the pieces of each size from the framing plans, then apply the formula per piece: thickness (in, nominal) x width (in, nominal) x length (ft) / 12 = bf. Multiply by the count, sum across sizes, and add a waste factor (often 5 to 15 percent for framing, higher for short-cut work). Divide the total by 1,000 to express it in MBF for pricing against a quoted MBF rate.
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How Ruh handles BF (board foot)
Ruh takes off the framing members from your plans by size and length, converts the package to board feet using the nominal-dimension formula, and applies your waste factors. It then prices the lumber against the MBF or per-piece rates in your own price book, and your estimator reviews the package before it goes in the bid.
See AI construction takeoff and estimating softwareBF (board foot): frequently asked questions
How many board feet are in a 2x4x8?+
2 x 4 x 8 / 12 = 5.33 board feet. A bunk of 294 pieces is therefore about 1,568 bf, which is why framing packages are usually discussed in MBF rather than individual board feet.
Do board feet use nominal or actual lumber dimensions?+
Nominal. A 2x10 is calculated as 2 inches by 10 inches even though the dressed piece measures 1.5 by 9.25 inches. The convention is consistent across the industry, so quotes and takeoffs match as long as everyone stays nominal.
What does MBF mean on a lumber quote?+
MBF is one thousand board feet (M is the Roman numeral for 1,000). A quote of $650 per MBF means $0.65 per board foot, so a 1,174 bf package prices at about $763.
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Figures on this page are illustrative. Construction estimates depend on project-specific conditions, source documents, market pricing, and professional judgment. Ruh's AI assists the estimator and does not replace professional review: your team reviews, validates, and approves every estimate, bid, and pricing decision.