How to calculate gravel
Gravel is sold by volume (cubic yards) or by weight (tons), so every job starts with length × width × depth. Measure in feet, divide the depth in inches by 12, multiply, and divide the cubic feet by 27 for cubic yards. Multiply cubic yards by the material's weight per yard to get tons.
Worked example — a 20 × 20 ft area, 4 in of #57 stone: 400 sq ft × (4 ÷ 12) = 133.3 cu ft ÷ 27 = 4.94 cu yd. At 1.35 tons per cubic yard that is 6.7 tons; order about 7.3 tons with the 10% extra most yards' own calculators add.
How much does a cubic yard of gravel weigh?
Weights below are loose, as delivered — the right basis for ordering. Defaults come from scale weights at a Georgia landscape yard (Mulch Pros) cross-checked against Martin Marietta's and Vulcan's quarry calculators; the range shows how much published factors disagree for the same product.
| Material | Tons per cu yd | Published range | 1 ton covers at 2 in |
|---|---|---|---|
| Pea gravel (3/8 in) | 1.4 | 1.35–1.6 | 116 sq ft |
| #57 stone / clean crushed stone (3/4 in) | 1.35 | 1.3–1.65 | 120 sq ft |
| Crusher run / #411 / road base | 1.45 | 1.3–1.62 | 112 sq ft |
| River rock (1–3 in) | 1.3 | 1.2–1.75 | 125 sq ft |
| Decomposed granite (DG) | 1.45 | 1.45–1.5 | 112 sq ft |
| Crushed concrete (recycled) | 1.3 | 1.21–1.4 | 125 sq ft |
| Limestone screenings / stone dust | 1.5 | 1.24–1.75 | 108 sq ft |
Loose vs. compacted: why base gravel needs more
Crusher run, crushed concrete, screenings and decomposed granite contain fines that pack down when you run a plate compactor over them. Penn State's Center for Dirt & Gravel Roads places 8 in of driving-surface aggregate loose to finish at 6 in — a factor of 1.33. So if a shed pad needs 4 in compacted, you spread about 5.3 in loose and order a third more. For a 10 × 12 ft pad that is about 3.1 tons of crusher run, not the 2.4 tons a simple volume calculator gives. Clean stone such as #57 and pea gravel has no fines and barely compacts, so it is ordered at its finished depth.
The opposite mistake also happens: quarry "base" weights such as Martin Marietta's 1.90 tons per cubic yard are compacted-in-place figures. Using them for loose decorative gravel over-orders by roughly 30%.
How deep should gravel be?
- Beds & ground cover: Decorative gravel needs at least 2 in to hide fabric (Stone Center); larger rock looks best at 3 in or more (Roseville suggests 3–6 in).
- Walkway: A typical build-up: about 2 in of pea gravel or DG on top of 3 in of compacted crusher run.
- Shed / slab base: 4 in compacted is the IRC base course under slabs; Quikrete places about 5 in and tamps it to 4. Under pavers, use the paver base calculator.
- New driveway: A typical new driveway: 4 in of #57 base stone on fabric, topped with 4 in of compacted crusher run. Penn State's road spec places 8 in loose to finish at 6 in.
- Driveway top-up: Top-dressing a worn driveway with about 2 in restores the surface; rebuild only where the base has failed.
- Play area: CPSC: fill 12 in so it never compresses below 9 in. 9 in of pea gravel protects falls up to 5 ft.
Compact base layers in lifts no thicker than 3 in (Unilock), and extend any base at least 6 in past the edge of what sits on it (Quikrete).
Bulk or bags?
A cubic yard is 54 bags of 0.5 cu ft (about 50 lb each). At big-box prices of roughly $5.50–$7 a bag that is $300–$375 per yard of stone, while bulk #57 runs about $35–$55 a ton and crusher run $24–$34 a ton at the quarry (American Rock Supply, 2026), plus a delivery fee — typically a flat $60–$125 within about 10 miles. Bags make sense for a few square feet or where a truck can't reach; for anything over about half a ton, bulk is usually cheaper even after delivery. The calculator shows the break-even for your prices.
Getting it home
A cubic yard of stone weighs 2,600–2,900 lb on Mulch Pros' scale — more than the nominal 1,000 lb payload of a half-ton pickup. Check the Tire & Loading sticker on your door jamb before loading. Yards send up to about 5 tons on a single-axle dump truck and up to 18 tons on a tandem. Make sure the truck has room to dump: Roseville Rock Supply asks for 10 ft of width, 14 ft of height clearance and firm, level ground.
Same stone, different names
Dense-graded base is called crusher run, crush & run, #411, 304, DGA, ABC, GAB, CA-6, 21A, 2A, flex base or Class 2 AB depending on the state — ask for the base or road stone your yard sells for driveways. Clean stone is sold by size number: #57 is about 3/4 in, #8 and #89 are smaller.
Common mistakes
- Ordering base gravel at its finished depth and running short once it is compacted.
- Using one weight for every stone — published factors run from 1.21 to 2.16 tons per cubic yard depending on product and whether it is loose or compacted.
- Skipping fabric under driveways and paths, so the stone slowly sinks into the soil.
- Spreading decorative gravel thinner than 2 in, which shows the fabric and lets weeds through.
- Overloading a pickup: one yard of gravel can be three times a half-ton's rated payload.
Laying pavers? The paver base calculator adds bedding sand and edge restraint. Pouring a slab on the base? Use the concrete slab calculator. For sandboxes and paver sand see the sand calculator, and for beds the mulch calculator. Driveway sizes: 12×50 at 4 in, new 10×50 driveway, 100 ft driveway.