How much gravel do I need for a 20 × 10 ft area, 3 inches deep?
For the worked example (20 × 10 ft area, 3 in deep) the material list is Gravel: 2.04 yd³ (calculated 55 cu ft, based on 10% extra allowance; weight at 1.5 tons / yd³ (rough starting value)). Quantities to buy are whole units rounded up from the calculated amounts. Enter your own measurements in the calculator above for your exact list.
How to use this calculator
- Measure the length and width of the area, and decide how deep the gravel will be.
- Keep or change the extra allowance. 10% is a starting value.
- Leave “Also estimate weight” on to see tons, and replace the density with your supplier’s figure.
- If you are buying bags, enter the bag volume to get a bag count.
- Copy, print or share the material list.
How this is calculated
- Volume (cu ft) = length × width × depth (depth in inches ÷ 12)
- With allowance = volume × (1 + allowance ÷ 100)
- Cubic yards = cubic feet ÷ 27
- Tons (optional estimate) = cubic yards × tons per cubic yard
- Bags (optional) = round up (cubic feet ÷ bag volume)
Geometry is deterministic. Material coverage, density, installation waste and product yield can vary. We expose those assumptions so you can replace them with the values printed on the products you are actually buying. Treat every result as an estimate. Items on your list are labelled Calculated (straight from your measurements) or Estimated (depends on an assumption), and “Buy” quantities are whole units rounded up.
Sources
No third-party figure is built into this calculator. Quantities come from geometry and from the values you can see and edit under “Assumptions” below, each labelled by where it comes from.
Last reviewed: . See the methodology.
Assumptions
These starting values are used until you change them. They are typical, not universal. Check the label on the product you are buying.
| Assumption | Starting value | Where it comes from |
|---|---|---|
| Cubic feet in a cubic yard | 27 | Mathematical – 3 ft × 3 ft × 3 ft |
| Inches in a foot | 12 | Mathematical – Depth in inches ÷ 12 gives feet |
| Gravel density | 1.5 tons / yd³ | Common planning default – A rough generic starting value with no published source. Ask your supplier. |
| Extra allowance | 10% | Common planning default |
| Bag volume (optional) | You enter it | You enter it (product / supplier) |
| Gravel density | 1.5 tons / yd³ | Common planning default |
Worked example
A 20 × 10 ft area, 3 in deep, with a 10% allowance and a 1.5 tons per cubic yard starting density:
- Gravel: 2.04 yd³ (≈ 3.06 tons) · 10% extra allowance; weight at 1.5 tons / yd³ (rough starting value)
Common questions
Is the tons figure exact?
No. Volume is geometry, but weight depends on the stone, moisture and gradation. The 1.5 tons per cubic yard default is a rough generic starting value, so ask your supplier for the real number and enter it under Assumptions.
How deep should gravel be?
This tool does not recommend depths. The 2, 3 and 4 inch buttons are just quick inputs. Depth depends on the project and the ground beneath it.
Do I round the cubic yards?
Quantities are rounded up, never down, so you do not come up short. Suppliers often sell in fractions of a yard or by the ton, so confirm with them.
Guides
- How Much Gravel Do I Need for a Driveway?Length, width and depth turned into cubic yards, with a tons estimate.
- Gravel Tons vs Cubic Yards: Which Number Should You Order?Why a cubic yard of gravel has no single weight.
- How Many Pavers Do I Need for a Patio?Patio area, paver size and waste turned into a paver count.
- How Much Concrete Do I Need for a Slab?Turn slab dimensions into volume and an order quantity.
- How Much Paver Base Do I Need?Base volume from area and chosen depth, in cubic yards and tons.