Lumber Calculator
Board feet from thickness × width × length, with waste and optional $/BF. Click any i for detail.
Lumber
Thickness (in)
i
T
Nominal thickness (e.g. 1.5 for 2×). |
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|---|---|
Width (in)
i
W
Nominal width (e.g. 3.5 for 2×4). |
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Length (ft)
i
L
Each piece length. |
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Number of pieces
i
Qty
Count of identical boards. |
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Price per board foot ($)
i
$/BF
Optional cost. |
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Waste (%)
i
Waste
Contingency for cuts. |
How to use this calculator
- Enter thickness, width, and length.
- Set piece count.
- Add $/BF and waste if desired.
- Read board feet and cost.
Results explained
Board feet = (T × W × length_ft) / 12 per piece. Multiply by quantity and a waste factor for purchasing. Nominal vs actual dimensions matter at the yard — enter what you buy.
Quick reference: board feet
BF/piece = T×W×L_ft / 12.
| Item | Detail |
|---|---|
| 2×4×8 (1.5×3.5×8) | 3.5 BF each |
| 20 pieces | 70 BF raw |
| +10% waste | 77 BF |
| Hardwood pricing | Often $/BF |
Also see the dedicated board-foot calculator for single-piece focus.
How the estimate is built
BF = pieces × (T×W×L)/12 × (1+waste%/100); cost = BF × price.
Example scenario
20 pcs 1.5×3.5×8' at $3.50/BF +10% → ~77 BF, ~$270.
FAQ
Nominal 2×4?
Often enter 1.5 × 3.5 actual.
Metric lumber?
Convert to inches/feet first.
Plywood?
Usually sheet coverage — see plywood calculator.
Linear feet only?
Still convert via board-foot formula if priced that way.