Gravel Calculator Square Feet
Accurate statistical gravel estimator for driveways, gardens, and landscaping. Uses sample depth measurements and confidence intervals to give you a reliable range — not just a single number.
1. Project area & depth samples
Separate by commas or spaces. More samples improve accuracy.
2. Confidence & material factors
Updated automatically with model year, but editable.
3. Your statistical gravel estimate
| Metric | Value |
|---|---|
| Count | — |
| Estimate | Cubic yards | Tons |
|---|---|---|
| Lower | — | — |
Depth sample distribution with mean (red line) and confidence bounds (dashed).
Interpretation of your results
| Confidence level | Practical meaning |
|---|---|
| 90% | Narrower range, less certainty that true mean depth is inside. |
| 95% (most common) | Balanced range: you can be 95% confident the true average depth lies between lower and upper bound. |
| 99% | Wider range, higher certainty, useful for critical projects. |
Model year & default density (tons/cy)
| Year | Typical density (trend) |
|---|---|
| 2024 | 1.40 |
| 2025 | 1.42 |
| 2026 | 1.44 |
| other | interpolated (±0.02 per year) |
Understanding each factor
- Square feet area: Length × width, or enter total directly. This is the base for volume.
- Depth samples: Because ground is rarely perfectly flat, multiple depth readings (inches) give a statistically sound average.
- Confidence level: Uses normal distribution (z‑score) to build a range around the mean depth. Higher confidence = wider range.
- Model year: Affects default gravel density (tons per cubic yard) – you can adjust manually. Trend: +0.02 tons/cy per year after 2024.
- Output: Volume in cubic yards and weight in tons. Always check upper bound for ordering extra material.
Use the Drywall Calculator (Square Feet) to quickly estimate material needs, or explore the full Feet & Inches Measurement Calculator category for all length and measurement tools.