lumber board feet calculator
The lumber board feet calculator provides professional, statistically robust volume estimation for lumber. It supports multi‑piece input, confidence intervals (90%, 95%, 99%), inflation‑adjusted pricing, and follows international statistical standards. Ideal for procurement, inventory, and cost analysis.
- Input multiple pieces with thickness (in), width (in), length (ft), and quantity.
- Automatic calculation of total board feet, mean, standard deviation, and variance.
- Confidence intervals for the true mean board foot value of your sample.
- Year‑based lumber price adjustment (2020–2025) using built‑in inflation factors.
- All tables responsive and fully compatible with WordPress builders.
Lumber data input
| Thickness (in) | Width (in) | Length (ft) | Quantity | Board feet (this row) | Action |
|---|---|---|---|---|---|
| 4.00 |
Statistical summary
| Sample size (n) | Total board feet | Mean board feet | Std deviation | Variance |
|---|---|---|---|---|
| 1 | 4.00 | 4.00 | — | — |
Confidence intervals for the mean
| Confidence level | Lower bound | Upper bound |
|---|---|---|
| 90% | — | — |
| 95% | — | — |
| 99% | — | — |
Inflation & price adjustment
| Year | Multiplier |
|---|---|
| 2025 | 1.00 |
| 2024 | 0.95 |
| 2023 | 0.90 |
| 2022 | 0.85 |
| 2021 | 0.80 |
| 2020 | 0.75 |
| Price / BF ($) | Unadjusted total | Inflation factor | Adjusted total ($) | Cost per piece ($) |
|---|---|---|---|---|
| 3.50 | 14.00 | 1.00 | 14.00 | 14.00 |
Frequently asked questions
What is a board foot?
A board foot is 1 inch thick × 12 inches wide × 1 foot long (144 in³). Our calculator uses the formula (T×W×L)/12.
How are confidence intervals computed?
We use the t‑distribution with n−1 degrees of freedom. For n<31 exact t‑values are applied; for larger n the normal approximation is used (z=1.645, 1.96, 2.576).
Where do inflation factors come from?
The factors reflect approximate lumber price indices (2025=1.00). They are illustrative; you may adjust the price manually to match current market.
Can I use metric units?
The calculator expects inches and feet. Convert metric: 1 in = 25.4 mm, 1 ft = 0.3048 m. Board feet remain an imperial measure.
Use the Roof Calculator (Square Feet) to estimate roof area quickly, or explore the full Feet & Inches Measurement Calculator category for all related measurement tools.