Standard Lumber Calculator
Board Foot Calculator for Lumber
Calculate board feet for standard dimensional lumber. Includes all common sizes from 1× to 4× boards.
Lumber Calculator
Select a common lumber size or enter custom dimensions
Actual dimension (not nominal)
Remember: Nominal sizes (like 2×6) are larger than actual dimensions. A 2×6 actually measures 1.5" × 5.5" after drying and planing.
1× Boards
Actual 3/4" thick. Used for trim, shelving, and light projects.
2× Lumber
Actual 1.5" thick. Standard framing lumber for walls, floors, and decks.
4× Posts
Actual 3.5" thick. Used for posts, beams, and heavy structural work.
6× Timbers
Actual 5.5" thick. Heavy timbers for posts, beams, and landscaping.
Frequently Asked Questions
What's the difference between nominal and actual size?
Nominal is the rough-cut size before drying and planing. Actual is the finished dimension. A 2×4 nominally is 2"×4" but measures 1.5"×3.5" actual.
Should I use nominal or actual dimensions?
Use actual dimensions for accurate board foot calculations. Our presets automatically use actual sizes for common lumber.
How many board feet in a typical 2×4×8?
Using actual dimensions: (1.5 × 3.5 × 8) ÷ 12 = 3.5 board feet per 8-foot 2×4.