Gravel Calculator | How Much Gravel Do I Need? (Tons, Cubic Yards)

How Much Gravel Do I Need?

Use this gravel calculator to estimate cubic yards and tons for driveways, patios, walkways, French drains, and landscaping. It is one of the construction calculators on OnSiteCalculator. Enter your dimensions, pick a gravel type, and set waste and compaction allowances — the calculator handles the rest.

Quick formula: (Length ft × Width ft × Depth in.) ÷ 324 = cubic yards. Multiply by density for tons.

Key inputs:

• Length and width (feet)
• Gravel depth (inches)
• Material type and density (tons per cubic yard)
• Waste allowance (percent)
• Compaction allowance (percent)
• Cost per ton (optional)

For a full walkthrough — including driveway depth guidelines, French drain sizing, and a worked example — see the how much gravel do I need guide.

Cubic Yards to Tons Gravel Calculator

The calculator converts volume to weight automatically using the density of your selected gravel type. Use this table as a quick reference when ordering by ton:

Formula: Tons = Cubic Yards × Density (t/yd³)

Example: 9.9 yd³ of crushed stone (1.50 t/yd³) = 9.9 × 1.50 = 14.85 tons

For pre-calculated conversion charts in both directions (yards → tons and tons → yards), see the cubic yards to tons gravel guide.

Gravel Coverage Per Ton Chart

One cubic yard covers different areas depending on how deep you spread it. Coverage per ton combines this with gravel density:

Rule of thumb: At 3 inches deep, one ton of pea gravel covers about 77 sq ft — roughly the size of an 8×10 room.

For a full coverage chart across all gravel types and depths, see the gravel coverage per ton guide.

How to Use This Gravel Calculator

1. Enter project dimensions — measure length and width of the gravel area in feet.
2. Enter gravel depth — specify depth in inches (2–6 inches for surface layers, 4–6 for driveways).
3. Select material type — choose from preset gravel types (pea gravel, crushed stone, river rock, granite, limestone) or enter a custom density.
4. Set allowances — add waste and compaction percentages to account for material loss, spreading, and post-installation settling.
5. Enter cost per ton (optional) — include your local price per ton to estimate total project cost.
6. Click Calculate to view coverage area, cubic yards, tons, and estimated cost.

Gravel Calculation Formula

Gravel volume and weight are calculated as follows:

• Depth (ft) = depth in inches / 12
• Cubic feet = length × width × depth (ft)
• Cubic yards = cubic feet / 27
• Base tons = cubic yards × density (tons/yd³)

Allowances are applied additively on the base volume:

• Waste yards = base yards × (waste% / 100)
• Compaction yards = base yards × (compaction% / 100)
• Total cubic yards = base yards + waste yards + compaction yards
• Total tons = total cubic yards × density
• Estimated cost = total tons × cost per ton

Worked Example: 20×40 ft Driveway

Crushed stone (1.50 t/yd³), 4 in. deep, 10% waste, 10% compaction:

1. Depth in feet: 4 / 12 = 0.333 ft
2. Area: 20 × 40 = 800 sq ft
3. Cubic feet: 800 × 0.333 = 266.4 ft³
4. Base cubic yards: 266.4 / 27 ≈ 9.9 yd³
5. Waste (10%): 9.9 × 0.10 ≈ 1.0 yd³
6. Compaction (10%): 9.9 × 0.10 ≈ 1.0 yd³
7. Total cubic yards: 9.9 + 1.0 + 1.0 ≈ 11.9 yd³
8. Total tons: 11.9 × 1.50 ≈ 17.8 tons

Gravel Depth Guide by Project Type

Common Mistakes to Avoid

Not accounting for compaction. Gravel compacts 10–15% after installation. Omitting a compaction allowance results in thin spots and insufficient depth after the first season of traffic.

Using the wrong density. Different gravel types have different densities. Using crushed stone density (1.5 t/yd³) for river rock (1.35 t/yd³) leads to a 10% over-order. Confirm density with your supplier.

Measuring depth in feet instead of inches. Entering 4 feet instead of 4 inches makes your estimate 12× too large. The calculator accepts depth in inches and converts automatically.

Not verifying supplier units. Some suppliers sell by the cubic yard, others by the ton. Confirm before ordering and use the matching output from the calculator.

For landscape beds adjacent to your gravel area, the mulch calculator estimates cubic yards and bags of mulch using the same volume formula. If you are pouring concrete over a gravel sub-base, the concrete slab calculator handles the concrete estimate on top.

Related Tools

• How Much Gravel Do I Need? Guide — Full planning guide with driveway depth guidelines, French drain sizing, waste factor table, and worked examples for every project type.
• Cubic Yards to Tons Gravel Guide — Pre-calculated conversion charts in both directions plus density values for every common gravel type.
• Gravel Coverage Per Ton Guide — Square footage coverage tables for pea gravel, crushed stone, river rock, and more at every common depth.
• Concrete Slab Calculator — Estimate cubic yards of concrete for slabs and driveways poured over a compacted gravel sub-base.
• Mulch Calculator — Calculate cubic yards and bags of mulch for landscape beds and play areas adjacent to your gravel project.