How Much Gravel Do I Need?
A five-step decision guide that takes you from a tape measure to an order-ready number in yards and tons — with the depth choices and worked examples that trip most people up.
How much gravel do you need? Multiply your area's length × width × depth in feet and divide by 27 for cubic yards, then multiply by 1.4–1.6 for tons. A 200 sq ft area at 3 inches deep needs 1.85 cubic yards — about 2.6 tons of #57 crushed stone. Add 5–10% for compaction, then order. Run your numbers in the gravel calculator.
The five-step decision guide
Every gravel estimate — any shape, any material — reduces to five decisions: area, depth, volume, density, and an allowance for settling. Work them in order and you cannot go wrong.
- Measure the area. Length × width in feet for rectangles; π × radius² for circles; outer area minus inner area for borders and rings. Irregular yard? Split it into rectangles and circles, calculate each, and add.
- Choose the depth. This is where projects succeed or fail — see the depth table below. The short version: 2–3″ paths, 4″ driveway surfaces, deeper only with layered bases.
- Compute cubic yards. cu yd = L(ft) × W(ft) × D(ft) ÷ 27. The 27 is cubic feet per cubic yard — the only constant you need memorize.
- Convert to tons. Suppliers sell by weight as often as volume. tons = cu yd × density: pea gravel/#57 ≈ 1.4, #411 ≈ 1.5, crusher run ≈ 1.6, river rock ≈ 1.35, decomposed granite ≈ 1.4, lava rock ≈ 0.7 (typical values — methodology).
- Add 5–10% and order. Compaction and settling consume the difference. Order the rounded-up number; a short load costs a second delivery fee.
The homepage calculator runs all five steps as you type, including circles, borders, metric units and the waste toggle.
Depth by project: the decision table
Pick depth by job, not by instinct — these are the ranges professional installers actually use.
| Project | Depth | Notes |
|---|---|---|
| Walkway / path surface | 2–3″ | Over 2–3″ compacted base; walkway guide |
| Driveway surface | 4″ | Over sub-base; driveway guide |
| New driveway, full build | 8–12″ total | Layered: sub-base + base + surface |
| French drain | Trench-sized | Typically 18–24″ deep trench; guide |
| Shed pad | 4–6″ | Compacted crusher run; shed pad guide |
| Patio surface | 2–3″ | Over 2–4″ base; patio guide |
| Decorative bed | 2″ | Over landscape fabric |
How much does one yard cover?
One cubic yard covers 81 square feet at 4 inches, 108 at 3 inches, and 162 at 2 inches — the three depths most projects use. Coverage = 27 ÷ depth in feet ÷ area, but the table is faster:
| Depth | Coverage per cu yd | Tons (crusher run, 1.6) | Bags (0.5 cu ft) |
|---|---|---|---|
| 2″ | 162 sq ft | 1.6 | 54 per yard |
| 3″ | 108 sq ft | 1.6 | 54 per yard |
| 4″ | 81 sq ft | 1.6 | 54 per yard |
| 6″ | 54 sq ft | 1.6 | 54 per yard |
Remember tons scale with material, not depth — swap crusher run for lava rock and the same yard drops to 0.7 tons.
Worked examples at real project scale
Three common projects, run through all five steps so you can pattern-match your own.
- Front walkway 3 ft × 40 ft at 2″ pea gravel: 3 × 40 × 0.167 = 20 cu ft ÷ 27 = 0.74 cu yd × 1.4 ≈ 1.04 tons → order 1.1.
- Single-car driveway 12 ft × 40 ft at 4″ crusher run: 160 cu ft ÷ 27 = 5.93 cu yd × 1.6 = 9.5 tons → order 10.
- Fire pit circle 10 ft diameter at 3″ #57: π × 5² × 0.25 = 19.6 cu ft ÷ 27 = 0.73 cu yd × 1.4 ≈ 1 ton.
Five mistakes that waste gravel money
Most gravel problems are depth and delivery mistakes, not math mistakes.
- Guessing the depth. The #1 error — 2″ vs 4″ doubles the order. Decide from the table above before calculating.
- Forgetting the base layer. Patios and driveways need a compacted base plus surface; calculate both.
- Ordering the exact number. No allowance means you'll be a few wheelbarrows short after compaction — always 5–10% up.
- Using the wrong density. Crusher run is 14% heavier per yard than #57; lava rock is half. Match the material dropdown.
- Skipping the depth check on delivery day. Spread a test strip one yard long and measure its depth before the truck dumps everything.
Last updated: October 2026