How the board foot calculator works
The formula and its dialects
Board feet = thickness(in) × width(in) × length(ft) ÷ 12. Rough-sawn hardwood bills by nominal size; surfaced (S4S) hardwood often bills by actual — a 1" rough board and a 3/4" S4S board are "the same" lumber in different dialects. Asking which convention the yard uses prevents the invoice surprise that feels like a scam and is actually typography.
Nominal sizes: the polite lie
Construction lumber is named before surfacing: a 2x4 is actually 1.5 × 3.5 inches, a 2x8 is 1.5 × 7.25. All framing math uses nominal (that is what yards sell); all fit-checking uses actual (that is what exists). The calculator prices in nominal because price tags do — the note exists because cabinet returns do not.
Using bf for project buying
Estimate a project in board feet (with 20% waste for hardwood defects), call the yard for a per-bf quote, and the phone number becomes real money before you drive. Hardwood yards sell shorter-than-listed boards too — "8/4 × 6 × 10ft" reads as two-inch-thick, six-inch-wide, ten-foot boards once the dialect is learned.