How Much Gravel Do I Need?
The short answer: measure your area, pick a depth, and run it through the pea gravel calculator. Here's how the math works and a few worked examples so you can eyeball it yourself.
The Quick Answer
You need three numbers: your area, your depth, and your material's density. Multiply area by depth to get volume, divide by 27 to get cubic yards, then multiply by density to get tons. That's the entire calculation — everything below just walks through it in more detail and gives you reference numbers for common projects. If you'd rather skip straight to a number, use the calculator above or the full pea gravel calculator.
Step-by-Step Calculation
1. Find your area. Measure length × width in feet. For odd shapes, break the space into rectangles and add them up — a patio with a curved edge can usually be approximated as two or three rectangles close enough for ordering purposes.
2. Choose your depth. Thin decorative layers use 2 inches; walkways and patios use 2–3 inches; driveways need 4+ inches of base material. See the full gravel depth guide for depth by project type.
3. Know your material's density. Most gravel weighs 1.4–1.5 tons per cubic yard — this is what converts your volume into a weight your supplier can quote and deliver. See the types of gravel guide if you're not sure which material you're ordering.
4. Do the math (or let the calculator do it). Cubic feet = area × depth (in feet). Cubic yards = cubic feet ÷ 27. Tons = cubic yards × density. Every calculator on this site runs this exact sequence.
Worked example, start to finish: a 150 sq ft gravel bed (the calculator's default above) at a 2-inch depth. Depth in feet: 2 ÷ 12 = 0.167 ft. Cubic feet: 150 × 0.167 = 25 cubic feet. Cubic yards: 25 ÷ 27 ≈ 0.93 cubic yards. Weight at pea gravel's 1.4 tons/yd³ density: 0.93 × 1.4 ≈ 1.3 tons. That's the whole calculation — the same four steps work at any size, for any material, once you swap in your own numbers and density.
Gravel Needed by Project Type
| Project | Typical size | Depth | Gravel needed |
|---|---|---|---|
| Garden border | 20 sq ft | 2 in | ≈0.12 yd³ (~0.17 tons) |
| Walkway | 60 sq ft | 2 in | ≈0.37 yd³ (~0.52 tons) |
| Patio | 200 sq ft | 3 in | ≈1.85 yd³ (~2.6 tons) |
| Single-car driveway | 600 sq ft | 4 in | ≈7.4 yd³ (~11.1 tons) |
Figures use a 1.4 tons/yd³ density and round up slightly for waste. Your project may vary — use the calculator above for exact numbers. See the gravel driveway calculator for a dedicated driveway version with material and layer options.
How Much Per Square Foot?
If you'd rather work per square foot than measure a full area, here's what one square foot needs at common depths (using pea gravel's 1.4 tons/yd³ density):
| Depth | Cubic yards per sq ft | Weight per sq ft |
|---|---|---|
| 2 in | 0.0062 yd³ | ≈17.3 lbs |
| 3 in | 0.0093 yd³ | ≈25.9 lbs |
| 4 in | 0.0123 yd³ | ≈34.6 lbs |
Multiply either figure by your total square footage for a fast estimate without touching a calculator — useful for a rough budget before you've finalized exact dimensions.
Always Add 10% for Waste
Every figure above is the theoretical minimum for a perfectly flat, perfectly measured space — real projects never work out that clean. Uneven ground eats extra material to level out, gravel compacts a little once it's spread and walked on, and some spills during unloading and spreading no matter how careful you are. Ordering exactly your calculated amount means running short partway through and needing a second, smaller delivery — usually at a worse per-ton price than your first order. Add 5% for a simple, flat, rectangular area, and closer to 10% for anything irregular, sloped, or heavily compacted, like a driveway base.
Frequently asked questions
How much gravel do I need for my project?
Measure your area in square feet, decide on a depth (2–4 inches for most projects), then multiply area by depth in feet and divide by 27 to get cubic yards. The pea gravel calculator does this automatically.
Should I order extra gravel?
Yes — order 5–10% more than your calculated amount to account for uneven ground, compaction, and spillage during spreading.
Do I need a base layer under gravel?
For walkways and patios, a compacted base of crushed stone plus landscape fabric under your decorative gravel prevents sinking and weed growth. For driveways, a proper base layer is essential — see the driveway calculator.
How much gravel do I need per square foot?
At a standard 2-inch depth, budget about 0.0062 cubic yards (roughly 17.3 lbs) per square foot. Multiply that by your total area, or use the calculator above for depths other than 2 inches.
What if my area isn't a simple rectangle?
Split it into two or more rectangles, calculate each separately, and add the totals together. For curved or irregular edges, measure the largest reasonable rectangle that fits and round up slightly — precision beyond that rarely changes the order by more than a few percent.