Lumber Calculator

A board foot (BF) is a unit of volume used to measure lumber in the United States and Canada. One board foot equals 144 cubic inches of wood — that's a piece of lumber 1 inch thick, 12 inches wide, and 12 inches long (or 1 inch × 12 inches × 1 foot). It's the standard unit for pricing and selling hardwood and rough-sawn lumber. Other common abbreviations include bd ft, FBM (foot board measure), and BF.

The standard board foot formula is:

Alternatively, if all measurements are in inches:

Example: A 2×4 that's 8 feet long:
BF = (2 × 4 × 8) ÷ 12 = 64 ÷ 12 = 5.33 BF

A standard 2×4×8 (nominal 2 inches × 4 inches × 8 feet) contains 5.33 board feet. Calculation: (2 × 4 × 8) ÷ 12 = 5.33 BF. If you're buying 10 of these, that's 53.33 BF total. Note that the actual dimensions are 1.5″ × 3.5″, but board feet for construction lumber is calculated using nominal sizes.

Nominal dimensions refer to the size of lumber before it's dried and planed — this is the name you see at the store (like "2×4"). Actual dimensions are the true measurements after surfacing. For example, a 2×4 actually measures about 1.5″ × 3.5″. Board feet for softwood construction lumber is almost always calculated using nominal dimensions. For hardwoods, actual dimensions are more commonly used. Our calculator lets you input whichever dimensions you prefer.

Lumber prices vary widely by species, grade, and market conditions. As a general guide (2024-2025 estimates):

• Construction softwood (pine, spruce, fir): $1.50 – $4.00 per BF
• Pressure-treated lumber: $2.00 – $5.00 per BF
• Red oak: $4.00 – $8.00 per BF
• Walnut: $8.00 – $15.00 per BF
• Cherry: $5.00 – $10.00 per BF
• Exotic hardwoods: $15.00 – $50.00+ per BF

Always check with local suppliers for current pricing. Use our calculator's price field to estimate your project costs.

Yes! Our calculator supports both imperial and metric units. You can input thickness and width in inches or centimeters, and length in feet, inches, meters, or centimeters. The calculator automatically converts all measurements to the standard board foot formula. This makes it perfect for international users or projects with mixed-unit specifications. Note that the output is always in board feet (BF), which is the standard lumber volume unit.

Linear feet measures only the length of a board, regardless of its thickness or width. Board feet measures the volume of wood, taking all three dimensions into account. For example, a 10-foot 2×4 is 10 linear feet but 6.67 board feet. When buying lumber, dimensional lumber (like 2×4s) is often priced per linear foot at retail stores, while hardwoods and rough-sawn lumber are typically priced per board foot. Understanding both helps you compare prices accurately.

It's recommended to add 10-15% extra to your calculated board feet to account for waste from cutting, knots, splits, and defects. For complex projects with many angled cuts (like roofing or staircases), consider adding 15-20%. Simply multiply your total board feet by 1.10 to 1.20. Our material list gives you the exact calculated total — you can then apply your waste factor manually or adjust quantities accordingly.

Board feet gives you a standardized way to compare lumber prices across different sizes, species, and suppliers. Without it, comparing a 1×6×8 to a 2×12×10 would be confusing. Board feet lets you calculate the actual volume of wood you're getting for your money. It's especially important for larger projects (decks, flooring, cabinetry) where small price differences per board foot can add up to hundreds of dollars.

Absolutely. For hardwood lumber, board feet is the standard pricing unit. Hardwood thickness is often expressed in quarters (4/4 = 1″, 5/4 = 1.25″, 6/4 = 1.5″, 8/4 = 2″). Simply enter the actual thickness in inches (e.g., 1 for 4/4, 1.5 for 6/4, 2 for 8/4). Use actual (not nominal) dimensions for hardwoods. Our calculator handles any dimension, making it suitable for both softwood construction lumber and fine hardwood projects.