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CalcSpectrum

Gravel Calculator

Calculate how much gravel you need in cubic yards and tons from driveway length, width, and depth.

Free to use · Instant results
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How It's Calculated

Formula

\text{volume}_{ft^3} = \text{length} \times \text{width} \times \frac{\text{depth}_{in}}{12} \\ \text{yd}^3 = \frac{\text{volume}_{ft^3}}{27} \\ \text{tons} = \text{yd}^3 \times \text{density}

This calculator finds gravel volume by multiplying driveway length and width (in feet) by depth (in inches, converted to feet). The volume converts to cubic yards for ordering, and to tons using a material density you provide — gravel bulk density varies meaningfully by material type (crushed stone, pea gravel, river rock) and moisture content, so there is no single correct constant. The default of 1.4 tons per cubic yard is a commonly cited typical figure; check your supplier's spec sheet for your specific material and adjust it.

Worked Examples

50 ft x 10 ft driveway, 4 in depth, density 1.4 tons/yd³

  1. Volume = 50 x 10 x (4/12) = 166.67 ft³
  2. Cubic yards = 166.67 / 27 ≈ 6.17 yd³
  3. Tons = 6.17 x 1.4 ≈ 8.65 tons

Adjusting density for a lighter material (1.2 tons/yd³)

  1. Same volume: 6.17 yd³
  2. Tons = 6.17 x 1.2 ≈ 7.4 tons

Frequently Asked Questions

Why do I need to enter a material density?

Gravel bulk density is not a fixed physical constant — it depends on the specific material (crushed stone, pea gravel, river rock, etc.) and how compacted or wet it is. Entering the density from your supplier's spec sheet gives an accurate tonnage instead of a one-size-fits-all guess.

What if I don't know my material's exact density?

1.4 tons per cubic yard is a commonly cited typical figure for crushed gravel and is used as the default, but for an accurate order quantity, check your supplier's product spec sheet or ask them directly.

Why is depth entered in inches but length and width in feet?

Driveway length and width are naturally measured in feet, while gravel layer depth is conventionally described in inches (e.g. "4 inches deep") — the calculator converts depth to feet internally before computing volume.