Gravel Calculator: How Much Gravel Do I Need?
Enter your area length, width, and depth, pick your material type, and get cubic yards, tons, 50 lb bag count, and a bulk-vs-bagged cost comparison — instantly, with no sign-up.
Project Dimensions
How the math works
Step 1 — volume in cubic yards
cu yd = (length_ft × width_ft × depth_in) ÷ 324 324 = 27 cu ft/yd × 12 in/ft. A canonical landscaping shortcut: multiply area by depth (in inches) and divide by 324.
Step 2 — apply waste / compaction allowance
cu yd (with waste) = cu yd × (1 + waste % ÷ 100) The waste allowance inflates both tonnage and bag count — you buy the waste-inclusive amount.
Step 3 — tons
tons = cu yd × density (ton/yd³) Material densities (US short tons per cubic yard): pea gravel 1.35, #57 stone 1.40, paver base 1.40, river rock 1.30, crusher run 1.40. Confirm exact weight with your supplier — density varies with moisture and stone source.
Step 4 — retail bags
bags = ⌈ cu yd × 54 ⌉ A standard 50 lb bag holds 0.5 cu ft. One cubic yard = 27 cu ft ÷ 0.5 = 54 bags.
For this project
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Suggestions update with your calculation — a bagged top-up shows different gear than a compacted driveway base.
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Frequently Asked Questions
Multiply your area length (ft) × width (ft) × depth (in), then divide by 324. That gives cubic yards. For example, a 20 × 10 ft area at 4 in deep is 200 × 4 ÷ 324 ≈ 2.47 cu yd. The divisor 324 = 27 cu ft/yd × 12 in/ft — the standard landscaping shortcut.
Multiply your cubic yards by the material density: pea gravel is 1.35 ton/yd³; crushed #57 stone is 1.40 ton/yd³; paver base and crusher run are 1.4 ton/yd³; river rock is 1.3 ton/yd³. So 2.47 cu yd of pea gravel = 2.47 × 1.35 ≈ 3.33 tons. Always confirm density with your supplier — it varies with moisture and source.
A standard 50 lb bag holds 0.5 cu ft. One cubic yard = 27 cu ft ÷ 0.5 = 54 bags. For smaller projects under half a cubic yard, bags are convenient; above that, bulk delivery is almost always cheaper.
Depth depends on use: 1–2 in for decorative topdressing, 2–3 in for garden paths, 4 in for driveways (surface layer), 6 in for heavy driveway base or paver sub-base. Use the waste allowance (10–15%) to account for spreading and compaction losses.
The 10% default allowance (set to 15% for driveways and compacted bases) accounts for material that spills, settles into voids, or compacts lower than the initial loose depth. It inflates both your ton order and bag count — you buy the waste-inclusive amount.
Pea gravel (3/8") is smooth and round — ideal for decorative beds and paths but does not compact. Crusher run (dense-grade) contains fines that lock together when compacted, making it the right choice for driveway bases, shed pads, and paver sub-bases. Both are 1.35–1.4 ton/yd³ but behave very differently under load.
At roughly 54 bags per cubic yard and about $6/bag, bagged gravel costs ~$324/yd³. Bulk delivery typically runs $30–$60/yd³ depending on your region and stone type — roughly 5–10× cheaper by volume once you exceed about 0.5–1 cubic yard. For small touch-up projects, bags win on convenience.