Gravel Calculator
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About the Gravel Calculator
Driveways, walkways, patios, drainage beds, shed bases — gravel is sold by the cubic yard (or ton), and eyeballing it is how people end up with either a second delivery fee or a pile they can't get rid of. The math itself is simple volume, but the unit juggling (feet for the area, inches for the depth, yards for the order) is where mistakes creep in.
Enter your area's length and width, the depth you're spreading, and a compaction allowance. You'll get cubic yards (the ordering unit), cubic feet and meters, an honest weight range, and — if you enter your supplier's quote — the cost. For multi-layer builds (fabric, base, top course), run each layer separately.
Building a driveway base layer specifically? Size the sub-base with the Road Base Calculator
The Gravel Formula
Three multiplications and a division — the trick is keeping units straight:
Volume (ft³) = Length (ft) × Width (ft) × Depth (ft) Cubic yards = ft³ ÷ 27 (then + 5–10% compaction) Weight ≈ yards × 1.4–1.7 tons
Worked example: a 20 × 10 ft walkway at 4″ deep is 20 × 10 × 0.333 = 66.7 ft³; with 5% allowance that's 70 ft³ ÷ 27 = 2.59 cubic yards, weighing roughly 3.6–4.4 tons. At $45 per cubic yard, about $117 of material.
Coverage per Cubic Yard
How far one cubic yard spreads at common depths (324 = the square-feet-per-yard constant at 1″):
| Depth | 1 yd³ covers | Typical use |
|---|---|---|
| 2″ | 162 sq ft | Top-up / decorative refresh |
| 3″ | 108 sq ft | Paths and walkways |
| 4″ | 81 sq ft | Standard driveway top course |
| 6″ | 54 sq ft | Driveway base layer / drainage |
Quick mental math: square feet × depth in inches ÷ 324 = cubic yards. A 600 sq ft driveway at 4″ is 600 × 4 ÷ 324 ≈ 7.4 yd³ before compaction allowance.
Choosing Depth by Project
Depth drives the whole order — typical build-ups:
- Walkways and garden paths: 2–3″ of ⅜–¾″ gravel over compacted soil or fabric.
- Driveways: a 4–6″ compacted base of larger crushed stone, topped with 2–3″ of smaller gravel — run each layer through the calculator separately.
- Drainage (french drains, foundation beds): 6″ or more of washed, uniform stone so water can move.
- Patios and shed bases: 4″ of compacted base under pavers or slabs, screeded level.
When in doubt between two depths, price both — the difference is usually one supplier trip, and under-built gravel work is the expensive kind to redo.
Frequently Asked Questions
How much gravel do I need for a 20x10 area?
At 4″ deep: 20 × 10 × 0.333 ÷ 27 ≈ 2.5 cubic yards, call it 2.6 with compaction allowance — roughly 3.6–4.4 tons. At 2″ deep, half that. Enter your exact dimensions above for the precise figure.
How many tons is a cubic yard of gravel?
Typically 1.4–1.7 US tons, depending on stone type, size, and moisture. Crushed limestone runs near the middle; wet or fine material weighs more. Your supplier can give the exact density for what they sell — enter their per-ton price and the calculator uses a 1.55 midpoint.
How deep should driveway gravel be?
A proper new driveway is built in layers totaling 6–9″: a 4–6″ compacted base of large crushed stone plus a 2–3″ top course of smaller gravel. Resurfacing an existing sound driveway only needs the 2–3″ top-up.
Why add a compaction allowance?
Gravel settles under compaction and works into the soil beneath, especially on soft or new ground. The 5% allowance suits firm, prepared bases; use 10% over soft ground, fresh excavation, or uneven grades. Landscape fabric underneath reduces the loss.
Should I buy bulk or bagged gravel?
Bags (typically 0.5 cu ft) make sense below about half a cubic yard — that's already ~27 bags. Beyond that, bulk delivery wins on price by a wide margin even with a delivery fee. One cubic yard equals 54 half-cubic-foot bags.
Does the calculator include the price of gravel?
No — gravel prices swing by region, stone type, and season, so a built-in price would just be wrong somewhere. Enter the quote from your local supplier (per yard or per ton) and the math is done at your real price.
Methodology. This calculator uses standard construction and material-estimation formulas. It is reviewed and maintained by the Vast Calculators editorial team.
Last updated · July 2026
Results are estimates for general use; verify critical figures independently.