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The short answer: multiply your area by the depth to get a volume, then convert to tons using roughly 1.4 tons per cubic yard. The long answer – the one that stops you from coming up two wheelbarrows short on delivery day – is below, with worked examples for the five most common gravel projects.
Enter your dimensions and get yards, tons, bags and cost instantly – with the waste allowance already included.
The gravel formula
Cubic feet = Length (ft) × Width (ft) × Depth (in) ÷ 12Cubic yards = Cubic feet ÷ 27Tons = Cubic yards × 1.4 (1.3 for pea gravel · 1.7 for crusher run)
Three things trip people up. First, depth is in inches but length and width are in feet – divide the depth by 12 before multiplying. Second, a cubic yard is 27 cubic feet, not 9. Third, the tons-per-yard figure depends on the material: round pea gravel is lighter than angular crushed stone, and dense crusher run with all its fines is heavier than both.
Step 1: Measure the area
For a rectangle, length × width. For a circle, 3.14 × radius². For anything irregular, break it into rectangles and triangles and add them up – or pace it out and estimate the square footage (a normal stride is about 2.5 ft). Always measure the area the gravel will actually cover, not the fence-to-fence dimensions of the yard.
Step 2: Decide on the depth
This is the number that most often goes wrong. Use this table:
| Project | Depth | Material |
|---|---|---|
| Decorative bed over landscape fabric | 2″ | Pea gravel, decorative chips |
| Garden path | 3″ | Pea gravel or 3/4″ crushed |
| Gravel patio | 3–4″ | Pea gravel over 2–3″ compacted base |
| Shed or hot tub pad | 4–6″ | #57 clean stone |
| Driveway top-up | 2–3″ | 3/4″ crushed gravel |
| New driveway | 8–12″ in layers | Crusher run base + 3/4″ top |
Step 3: Convert to yards and tons
Divide cubic feet by 27 for yards, then multiply by the material’s tons-per-yard. Then – and this is the step everyone skips – add 5–10% for waste, or 15–20% if the layer will be compacted. Gravel spills, the ground is never perfectly level, and the delivered load is measured loose.
Worked examples
Example 1: Gravel path, 30 ft × 3 ft, 3″ deep (pea gravel)
- Area: 30 × 3 = 90 sq ft
- Cubic feet: 90 × 3 ÷ 12 = 22.5 ft³
- Cubic yards: 22.5 ÷ 27 = 0.83 yd³
- Tons: 0.83 × 1.3 = 1.08 tons → with 5% waste, 1.15 tons (or 47 bags of 0.5 cu ft)
Example 2: Shed pad, 10 ft × 12 ft, 4″ of #57 stone
- Area: 120 sq ft → 120 × 4 ÷ 12 = 40 ft³ = 1.48 yd³
- Tons: 1.48 × 1.42 = 2.1 tons → with 10% allowance, 2.3 tons
Example 3: Patio, 12 ft × 14 ft, 3″ of pea gravel over a 3″ compacted base
- Area: 168 sq ft
- Base: 168 × 3 ÷ 12 = 42 ft³ = 1.56 yd³ × 1.2 (compaction) = 1.87 yd³ × 1.69 = 3.2 tons crusher run
- Top: 42 ft³ = 1.56 yd³ × 1.3 = 2.0 tons × 1.05 = 2.1 tons pea gravel
Example 4: Driveway top-up, 12 ft × 50 ft, 2″ of 3/4″ gravel
- Area: 600 sq ft → 600 × 2 ÷ 12 = 100 ft³ = 3.7 yd³
- Tons: 3.7 × 1.42 = 5.3 tons → with 5%, 5.5 tons – one small dump-truck load
Example 5: New driveway, 12 ft × 50 ft, 6″ crusher run base + 3″ top
- Base: 600 × 6 ÷ 12 = 300 ft³ = 11.1 yd³ × 1.2 = 13.3 yd³ × 1.69 = 22.5 tons
- Top: 600 × 3 ÷ 12 = 150 ft³ = 5.6 yd³ × 1.42 × 1.05 = 8.3 tons
- Total: about 31 tons – two tandem loads
Gravel coverage chart
If you already know how many tons you have (or how much your budget buys), read the chart backwards: at 3″ deep, one ton of 3/4″ gravel covers about 76 sq ft.
| Material | Density | Tons per yd³ | sq ft per ton at 2" | sq ft per ton at 3" | sq ft per ton at 4" | sq ft per ton at 6" |
|---|---|---|---|---|---|---|
| Gravel, 3/4"–1" (general) | 105 lb/ft³ | 1.42 | 114 | 76 | 57 | 38 |
| Pea gravel (3/8") | 96 lb/ft³ | 1.30 | 125 | 83 | 63 | 42 |
| Crushed stone #57 (3/4") | 105 lb/ft³ | 1.42 | 114 | 76 | 57 | 38 |
| Crusher run / #411 / ABC (dense) | 125 lb/ft³ | 1.69 | 96 | 64 | 48 | 32 |
| Stone dust / screenings | 100 lb/ft³ | 1.35 | 120 | 80 | 60 | 40 |
| River rock, 1–3" | 100 lb/ft³ | 1.35 | 120 | 80 | 60 | 40 |
| Decorative / landscape rock | 100 lb/ft³ | 1.35 | 120 | 80 | 60 | 40 |
| Lava rock | 50 lb/ft³ | 0.68 | 240 | 160 | 120 | 80 |
| Limestone, crushed | 100 lb/ft³ | 1.35 | 120 | 80 | 60 | 40 |
| Granite, crushed | 105 lb/ft³ | 1.42 | 114 | 76 | 57 | 38 |
| Recycled concrete | 95 lb/ft³ | 1.28 | 126 | 84 | 63 | 42 |
Coverage = 2,000 lb ÷ (density × depth in feet). Figures are for loose material; add 5–10% for waste and up to 20% for compacted base layers.
Yards or tons – which should you order in?
Whichever your supplier uses, but compare quotes in the same unit. Since gravel is about 1.4 tons per yard, a price of $45 per ton is the same as $63 per yard. Bagged gravel is sold by volume (0.5 cu ft, 54 bags to the yard) and costs several times more per yard than bulk – worth it only for small jobs.
Five mistakes that leave you short
- Forgetting to divide inches by 12. The classic error – it makes the answer 12× too big or, if you “fix” it wrongly, 12× too small.
- Using 1 ton = 1 yard. A yard of gravel is about 1.4 tons. Ordering “3 tons” when you worked out 3 yards leaves you 30% short.
- No compaction allowance on base layers. Crusher run shrinks 15–20% under a plate compactor.
- Measuring the horizontal footprint of a slope. On a bank, the surface area is bigger than the plan area.
- Guessing the depth. Half an inch extra over 500 sq ft is almost a ton of gravel.
Check your own project – choose the material, set the depth and the calculator handles yards, tons, bags, waste and cost.
Frequently asked questions
How much gravel do I need for 100 square feet?
At 2″ deep: 0.62 cubic yards (about 0.9 tons). At 3″ deep: 0.93 cubic yards (about 1.3 tons). At 4″ deep: 1.23 cubic yards (about 1.75 tons), using 1.42 tons per yard for 3/4″ gravel.
How many tons of gravel do I need for a 10×20 driveway?
For a 2″ top-up of 3/4″ gravel: 200 sq ft × 2 ÷ 12 = 33 ft³ = 1.23 yd³ ≈ 1.75 tons; order about 1.85 tons with waste. For a new 10″ driveway in layers (6″ crusher run base + 4″ top), about 11 tons.
How much area does a ton of gravel cover?
About 114 sq ft at 2″, 76 sq ft at 3″, 57 sq ft at 4″ and 38 sq ft at 6″ for typical 3/4″ gravel. Pea gravel covers about 10% more; crusher run about 15% less.
