Lumber Calculator
Find board feet, total volume, and material cost for framing, decking, furniture, and fencing projects.
Your Lumber Estimate
- Enter board dimensions — length and width of a single board. For framing, enter the stud or joist size.
- Set thickness — use the presets for standard sizes. A "2x" board is actually 1-1/2" thick after milling.
- Add waste — 10% suits most straight-cut projects. Go to 15-20% for hardwood where cutting errors are expensive.
- Enter price per BF — check your supplier. Framing pine runs $0.80-$1.50/BF; hardwoods vary widely by species.
- Round up when ordering — always round to the next whole board. Running short mid-project costs more time than one extra board.
What Is a Board Foot and When Does It Matter?
A board foot (BF) measures lumber volume. One BF equals a piece 1 inch thick, 12 inches wide, and 1 foot long — 144 cubic inches total. Hardwood at sawmills and specialty yards is priced by the board foot because boards come in random widths and lengths, and price based on volume makes comparison fair. The formula: (Thickness in inches x Width in inches x Length in feet) / 12.
Standard construction softwood — 2x4s, 2x6s, dimensional pieces — is typically sold by the piece or linear foot at home centers. But knowing board footage still helps with cost comparison and ordering from a lumber yard that prices by volume.
Nominal vs actual lumber dimensions
Every labeled lumber size is larger than what you receive. Mills dry and surface lumber after cutting, reducing every dimension. This matters most when buying hardwood priced by actual board feet:
| Nominal size | Actual size | Board feet (8 ft) | Typical use |
|---|---|---|---|
| 1x4 | 3/4" x 3-1/2" | 1.75 BF | Trim, face frames, shelving |
| 1x6 | 3/4" x 5-1/2" | 2.75 BF | Siding, fence boards, shelving |
| 1x8 | 3/4" x 7-1/4" | 3.63 BF | Wide shelving, fascia, wainscoting |
| 1x12 | 3/4" x 11-1/4" | 5.63 BF | Cabinet sides, wide panels |
| 2x4 | 1-1/2" x 3-1/2" | 5.33 BF | Wall studs, blocking |
| 2x6 | 1-1/2" x 5-1/2" | 8.00 BF | Rafters, deck joists, exterior walls |
| 2x8 | 1-1/2" x 7-1/4" | 10.67 BF | Floor joists, headers, stair stringers |
| 2x10 | 1-1/2" x 9-1/4" | 13.33 BF | Long-span joists, large headers |
| 2x12 | 1-1/2" x 11-1/4" | 16.00 BF | Stair stringers, heavy headers |
| 4x4 | 3-1/2" x 3-1/2" | 10.67 BF | Posts, deck piers, fence posts |
| 6x6 | 5-1/2" x 5-1/2" | 26.67 BF | Heavy posts, pergola columns |
Use nominal dimensions when ordering from most suppliers — they calculate board feet the same way. Use actual dimensions when buying hardwood from a sawmill or specialty yard pricing by the board foot.
Lumber prices by species (2025-2026 US averages)
| Species | Type | Price per board foot | Common uses |
|---|---|---|---|
| Douglas Fir / Pine | Softwood | $0.80-$1.50 | Framing, structural lumber |
| Pressure-treated pine | Softwood | $1.25-$2.50 | Decking, ground contact, sill plates |
| Cedar | Softwood | $2.00-$4.00 | Decking, siding, outdoor furniture |
| Poplar | Hardwood | $3.00-$5.00 | Paint-grade cabinets, furniture |
| Red oak | Hardwood | $5.00-$8.00 | Flooring, furniture, stair treads |
| Hard maple | Hardwood | $5.50-$9.00 | Butcher block, counters, cabinetry |
| White oak | Hardwood | $6.00-$11.00 | Furniture, flooring, outdoor projects |
| Cherry | Hardwood | $8.00-$14.00 | Fine furniture, cabinetry, trim |
| Black walnut | Hardwood | $10.00-$18.00 | Furniture, live edge slabs, turning |
Prices vary by region, grade (FAS vs #1 Common vs #2), surface condition (rough vs S4S), and market conditions. Always get current quotes from your supplier.
Board foot formulas
Two equivalent ways to calculate — use whichever unit your tape measure gives you:
Length in inches = BF = (Thickness" x Width" x Length") / 144
Multiple boards = Total BF = BF per board x Number of boards
With waste = Order qty = Total BF x (1 + Waste %)
Material cost = Total cost = Order qty x Price per BF
For softwood framing lumber, use nominal dimensions — that's what suppliers use for pricing. For hardwood ordered from a sawmill, use actual surfaced dimensions since that's what you physically receive.
Related Calculators
Board feet are the starting point for framing, decking, and woodworking estimates. Browse the construction calculator collection.
Frequently Asked Questions
How many board feet in a 2x4 that is 8 feet long?
Using nominal dimensions: (2 x 4 x 8) / 12 = 5.33 board feet. At 10 feet it's 6.67 BF; at 12 feet exactly 8 BF. If your lumber yard prices hardwood by actual dimensions, use 1.5 x 3.5 instead — the result drops to 3.5 BF for the same physical board.
What is the difference between board feet and linear feet?
Linear feet measure only length. Board feet measure volume — thickness and width are factored in too. A 10-foot 2x4 and a 10-foot 2x6 are both 10 linear feet, but the 2x6 contains 10 BF while the 2x4 is 6.67 BF. Use linear feet for trim and molding. Use board feet when comparing lumber cost across different sizes or buying hardwood by volume.
Should I use nominal or actual dimensions?
Use nominal dimensions (2x4, 1x6, etc.) for softwood framing lumber — most suppliers price it this way. Use actual dimensions for hardwood from a sawmill or specialty yard, where you're paying for the real volume you receive. When unsure, ask your supplier which measurement they use.
How much extra lumber should I order?
10% is standard for simple straight-cut framing. Add 15% for diagonal cuts, multiple corners, or work with many openings. Budget 20% for expensive hardwood — defect culling, grain matching, and mistakes all add up. An extra board returned to the store is far cheaper than a second trip or delivery.
How many board feet are in a bundle of lumber?
Bundle sizes vary by supplier. A common bundle of 8-foot 2x4s contains 208 pieces (about 1,109 board feet). A bundle of 8-foot 2x6s typically holds 168 pieces (about 1,344 board feet). Bundle pricing at a lumber yard is usually 15-25% cheaper per board foot than buying off the rack at a home improvement store.