Lumber Calculator
Calculate board feet, weight, and cost for any lumber purchase. Choose from 11 wood species with density data and 8 dimensional lumber presets.
🪓 Lumber Calculator
BOARD FEET
WEIGHT
COST
💡 How to Calculate Board Feet
Lumber is the backbone of US construction and woodworking. Whether you're framing a house, building a deck, crafting furniture, or finishing a trim project, accurately calculating board footage, weight, and cost is essential to avoid over-ordering and wasted material.
The calculator above includes 11 wood species with density data (for weight estimation), 8 dimensional lumber presets (2×4 through 4×4 with actual sizes), and a weight output so you know how much your lumber order weighs before delivery.
For sheathing, see our plywood calculator. For fencing, try our fence calculator. Measure area with our square footage calculator.
Wood Species Density Chart
Wood density determines weight and hardness. Density values below are for air-dried wood (~12% moisture content). Green (freshly cut) lumber can weigh 50–100% more due to moisture.
| Species | Type | Density (lbs/cu ft) | 8 ft 2×4 Weight | Cost per BF |
|---|---|---|---|---|
| SPF (Spruce-Pine-Fir) | Softwood | 28 | ~9 lbs | $2–$4 |
| Pressure-Treated Pine | Softwood | 35 | ~11 lbs | $3–$5 |
| Douglas Fir | Softwood | 34 | ~11 lbs | $3–$5 |
| Western Red Cedar | Softwood | 23 | ~7 lbs | $5–$8 |
| Redwood | Softwood | 28 | ~9 lbs | $6–$10 |
| Poplar | Hardwood | 29 | ~9 lbs | $3–$5 |
| Red Oak | Hardwood | 44 | ~14 lbs | $5–$8 |
| White Oak | Hardwood | 47 | ~15 lbs | $6–$9 |
| Hard Maple | Hardwood | 44 | ~14 lbs | $5–$8 |
| Black Walnut | Hardwood | 38 | ~12 lbs | $8–$15 |
| Cherry | Hardwood | 35 | ~11 lbs | $6–$10 |
Step-by-Step Board Foot Calculation
Step 1: Measure the Board
Measure length in feet, width in inches, and thickness in inches. For dimensional lumber (2×4, 2×6, etc.), use the nominal dimensions for board foot pricing — lumberyards price by nominal size.
Step 2: Calculate Board Feet
Formula: Board Feet = (Length ft × Width in × Thickness in) ÷ 12
Example: An 8 ft × 6" × 1" board: (8 × 6 × 1) ÷ 12 = 4 board feet
Example: A 10 ft 2×6: (10 × 6 × 2) ÷ 12 = 10 board feet
Step 3: Estimate Weight
Convert board feet to cubic feet (÷ 12), then multiply by the wood's density (lbs/cu ft).
Example: 4 BF of red oak: 4 ÷ 12 = 0.333 cu ft × 44 lbs/cu ft = 14.7 lbs
Dimensional Lumber: Nominal vs. Actual Sizes
| Nominal | Actual Size | Board Feet per 8 ft | Weight (SPF, 8 ft) |
|---|---|---|---|
| 1×4 | ¾" × 3½" | 2.67 BF | ~4.4 lbs |
| 1×6 | ¾" × 5½" | 4.00 BF | ~6.2 lbs |
| 1×8 | ¾" × 7¼" | 5.33 BF | ~8.2 lbs |
| 2×4 | 1½" × 3½" | 5.33 BF | ~9.0 lbs |
| 2×6 | 1½" × 5½" | 8.00 BF | ~13.1 lbs |
| 2×8 | 1½" × 7¼" | 10.67 BF | ~17.3 lbs |
| 2×10 | 1½" × 9¼" | 13.33 BF | ~22.1 lbs |
| 2×12 | 1½" × 11¼" | 16.00 BF | ~26.8 lbs |
| 4×4 | 3½" × 3½" | 10.67 BF | ~18.2 lbs |
2025 US Lumber Cost Guide
| Lumber Type | Cost per BF | 8 ft 2×4 Price | Best For |
|---|---|---|---|
| SPF (#2 grade) | $2–$4 | $3–$6 | Framing, general construction |
| Pressure-Treated | $3–$5 | $5–$9 | Decks, fences, ground contact |
| Douglas Fir | $3–$5 | $5–$8 | Structural, beams, posts |
| Cedar (WRC) | $5–$8 | $8–$14 | Decks, siding, outdoor furniture |
| Red Oak | $5–$8 | $10–$16 | Furniture, cabinets, flooring |
| Black Walnut | $8–$15 | $16–$30 | Fine furniture, cutting boards |
| Cherry | $6–$10 | $12–$20 | Furniture, trim, cabinetry |
Lumber grading: #1 (select/premium) costs 20–50% more than #2 (standard). FAS (First and Seconds) is the top hardwood grade. Common #1 is standard for cabinet-grade hardwood.
Lumber Buying Tips
- Buy 10–15% extra for waste, defects, and miscuts
- Kiln-dried (KD) lumber is more stable than green; look for "KD" or "HT" (heat-treated) stamps
- Board foot pricing is standard for hardwoods and rough-sawn lumber; dimensional softwood is usually priced per piece
- Check for straight boards at the store — sight down the length for twist, bow, and warp
- Bulk discounts are common at lumberyards (not big-box stores) for orders over 100 BF