How Much Gravel Do I Need? A Practical Guide
A simple three-step framework for estimating gravel quantity — measure, choose depth, account for density — plus worked examples for the most common projects.
The fastest way to answer "how much gravel do I need?" is to use the calculator on the homepage. But if you want to understand what it's doing — or you're standing in a quarry parking lot without your phone — here's the math.
The three-step framework
Every gravel estimate is just three steps. Get each one right and the answer is right.
- Measure the area in square feet. Length × width for a rectangle, π × radius² for a circle, ½ × base × height for a triangle. For irregular shapes, break the area into simpler pieces and add them up.
- Pick the depth in inches. 2" for paths and decorative beds, 4" for paver bases and driveway tops, 6" for full driveways. (See our depth guide for the details.)
- Convert to cubic yards or tons. Cubic yards = sq ft × depth-in-inches ÷ 324. Tons ≈ cubic yards × 1.35 for crushed stone.
Worked examples
Example 1: Small garden path
- Path: 3 ft wide × 25 ft long = 75 sq ft
- Depth: 2 inches of pea gravel
- Volume: 75 × 2 ÷ 324 = 0.46 yd³
- Weight: 0.46 × 1.22 (pea gravel factor) = 0.57 tons (~1,140 lb)
- With 10% buffer → 0.5 yd³ or about 1,250 lb. Well under most quarry minimums — order bagged.
Example 2: 12 × 14 paver patio
- Area: 168 sq ft
- Base: 4 inches of CA6
- Bedding: 1 inch of concrete sand
- CA6 volume: 168 × 4 ÷ 324 = 2.07 yd³ → ~2.7 tons
- Sand volume: 168 × 1 ÷ 324 = 0.52 yd³ → ~0.7 tons
- With 10% buffer → order 3 tons of CA6 and 1 ton of concrete sand
Example 3: Single-car driveway, 10 × 50 ft
- Area: 500 sq ft
- Base: 4 inches CA6 → 500 × 4 ÷ 324 = 6.17 yd³ → 8.3 tons
- Top: 2 inches #57 → 500 × 2 ÷ 324 = 3.09 yd³ → 4.3 tons
- With 10% buffer → 9.5 tons base + 5 tons top = ~14.5 tons total
Why you should add a buffer
Three things eat into the gravel you ordered:
- Compaction. Loose gravel settles 15–20% under a compactor.
- Spillage. When you dump from a truck and spread by hand, 3–8% ends up where you didn't plan.
- Measurement error. A perfect rectangle on paper is rarely a perfect rectangle on the ground.
The 10% default buffer covers all three for most projects. Bump it to 15% if you're working on a slope or with an irregular shape; drop it to 5% if you have a perfectly flat, square area.
Quick coverage reference
Use this as a back-of-envelope check before you measure. All numbers are for crushed stone (#57, ~2,750 lb/yd³) and include a 10% buffer. Lighter materials like lava rock cover about 80% more area per ton; heavier dense-grade base materials cover about 5% less.
| Project size | 2" deep | 3" deep | 4" deep | 6" deep |
|---|---|---|---|---|
| 50 sq ft | 0.5 tons | 0.7 tons | 0.9 tons | 1.4 tons |
| 100 sq ft | 1.0 tons | 1.4 tons | 1.9 tons | 2.8 tons |
| 200 sq ft | 1.9 tons | 2.8 tons | 3.7 tons | 5.6 tons |
| 500 sq ft | 4.7 tons | 7.0 tons | 9.3 tons | 14.0 tons |
| 1,000 sq ft (small driveway) | 9.4 tons | 14.0 tons | 18.7 tons | 28.0 tons |
| 1,500 sq ft (long driveway) | 14.0 tons | 21.0 tons | 28.0 tons | 42.0 tons |
For exact numbers matched to your specific shape, depth, and material, use the main gravel calculator. For converting between cubic yards and tons by material, see our cubic yards to tons guide.