Rock Calculator Square Feet
This enterprise-grade calculator estimates the required rock (in tons) and total cost for a project based on square footage, depth, and rock type. It incorporates statistical confidence intervals (90%, 95%, 99%) using a sample size input, inflation adjustment, and provides graphical visualization of uncertainty. All calculations follow international statistical standards and are suitable for professional deployment worldwide.
Key Features
- Global unit compatibility (feet/inches, tons, USD)
- Confidence intervals with t‑distribution (sample size ≥2)
- Inflation adjustment from base year to target year
- Interactive chart with point estimate and error bars
- Responsive tables with detailed statistics
Input Parameters
Results & Statistical Analysis
Table 1: Input Summary
| Parameter | Value |
|---|---|
| Area | 500 sq ft |
| Depth | 3 in |
| Rock Type | Gravel |
| Base Year | 2020 |
| Target Year | 2025 |
| Inflation | 2.5% |
| Sample Size | 30 |
Table 2: Rock Reference Data
| Type | Density (tons/ft³) | Base Price ($/ton) | Adjusted Price ($/ton) |
|---|
Table 3: Sample Statistics
| Statistic | Value |
|---|---|
| Mean Price (adj.) | – |
| Std Dev (adj.) | – |
| Std Error | – |
| Degrees of Freedom | – |
| t-critical (selected) | – |
Table 4: Confidence Intervals for Cost
| Level | Lower ($) | Upper ($) | Margin (±$) |
|---|
Table 5: Estimated Output
| Metric | Value |
|---|---|
| Volume (ft³) | – |
| Tons Required | – |
| Point Estimate Cost ($) | – |
Graphical Visualization: Cost Estimate & 90%/95%/99% CI
FREQUENTLY ASKED QUESTIONS
HOW IS THE AMOUNT OF ROCK CALCULATED?
Volume in cubic feet is area (sq ft) × depth (inches) / 12. Tons = volume × density (tons/ft³). Densities vary by rock type.
WHAT DO THE CONFIDENCE INTERVALS MEAN?
We calculate 90%, 95%, and 99% confidence intervals for the estimated cost based on sample size and price variability. A wider interval means higher uncertainty.
HOW IS INFLATION ADJUSTMENT APPLIED?
The base price per ton is adjusted using the compound inflation rate from the base year to the target year: adjusted = base × (1 + inflation/100)^(target – base).
WHAT SAMPLE SIZE SHOULD I USE?
Larger sample sizes (≥30) produce narrower, more reliable intervals. For accurate results, use actual historical price data points.
Use the Lumber Board Feet Calculator to estimate board footage quickly, or explore the full Feet & Inches Measurement Calculator category for all measurement and length conversion tools.