Gravel, Mulch and Topsoil Calculator
To find how much gravel, mulch or topsoil you need, multiply the area in square feet by the depth in feet (depth in inches divided by 12) to get cubic feet, add an allowance, then divide by 27 for cubic yards. Divide cubic feet by the bag size for bags. For gravel, multiply cubic yards by the density: a state DOT table lists loose, dry gravel at 2,565 lb per cubic yard, about 1.28 tons.
Gravel, mulch and topsoil calculator
Choose the material, then enter the area and the depth. Results update as you type and are saved in the page address so you can bookmark them. Nothing leaves your browser.
How the calculator works
One engine serves every material: area times depth gives volume, which converts to cubic yards and bags. Only the aggregates get a weight, because only they have a published density.
cubic feet = area (sq ft) × depth (in) ÷ 12 cubic yards = cubic feet × (1 + waste ÷ 100) ÷ 27 bags = round up (cubic feet × (1 + waste ÷ 100) ÷ bag size in cu ft) tons = cubic yards × lb per cubic yard ÷ 2000 (gravel and sand only) coverage = 324 ÷ depth (in) = sq ft covered by 1 cubic yard
- area
- length × width, or π × (diameter ÷ 2)² for a circle
- lb per cubic yard
- loose weight from the Nevada DOT table (source 2)
- 2000
- pounds in a short ton (source 3)
Worked example
Given: a 10 ft × 10 ft planting bed; 3 inches of mulch; 10% allowance; bags of 2 and 3 cubic feet.
- Area:
10 × 10 = 100 sq ft - Volume:
100 × 3 ÷ 12 = 25 cu ft = 0.93 cu yd - With the allowance:
25 × 1.10 = 27.5 cu ft = 1.02 cu yd - 2 cubic foot bags:
27.5 ÷ 2 = 13.75 → 14 - 3 cubic foot bags:
27.5 ÷ 3 = 9.17 → 10
Answer: 1.02 cubic yards, so about 1 yard in bulk or 14 bags of 2 cu ft (10 of 3 cu ft). Texas A&M AgriLife Extension gets 0.93 yards for the same bed before any allowance (source 1). For gravel, 200 sq ft at 4 inches with the same allowance is 2.72 cubic yards, or 3.48 tons at 2,565 lb per cubic yard.
Weight of aggregates
| Material | Pounds per cubic yard | Tons per cubic yard | Source |
|---|---|---|---|
| Gravel, loose and dry | 2,565 | 1.28 | Source 2 |
| Gravel, pit run | 3,240 | 1.62 | Source 2 |
| Crushed limestone | 2,625 | 1.31 | Source 2 |
| Crushed granite | 2,778 | 1.39 | Source 2 |
| Sand, dry and loose | 2,700 | 1.35 | Source 2 |
Tons per cubic yard is pounds ÷ 2000 (source 3). The DOT says aggregate weights vary with location and moisture and the figures are for estimating only; ask your supplier for the weight of the stone you are buying.
What a cubic yard covers
| Depth | Sq ft per cubic yard | Cubic feet per 100 sq ft | Source |
|---|---|---|---|
| 1 inch | 324 | 8.33 | Source 1 formula |
| 2 inches | 162 | 16.67 | Source 1 formula |
| 3 inches | 108 | 25 | Source 1 formula |
| 4 inches | 81 | 33.33 | Source 1 formula |
| 6 inches | 54 | 50 | Source 1 formula |
Computed from the extension’s formula: 27 cubic feet per cubic yard, depth divided by 12.
Assumptions and limits
- Even depth over a flat area. For a sloping or uneven area, split it into sections and add the results.
- Tons use loose, dry weights from one state DOT table. Wet or compacted material weighs more, and local stone differs. Ask your supplier for the figure that applies.
- The 10% allowance is a planning default, not a published figure. Raise it for a compacted base.
- Mulch and topsoil are sold by volume, so the calculator gives cubic yards and bags only.
- Bag sizes of 2 and 3 cubic feet are common; use the volume printed on your bag if it differs and divide the cubic feet shown by it.
- Published figures are as of 2026-11-13.
Frequently asked questions
How do I calculate cubic yards of mulch or soil?
Texas A&M AgriLife Extension gives the formula: cubic yards = length (ft) × width (ft) × depth (in ÷ 12) ÷ 27. Its example is a 10 × 10 ft bed with 3 inches of mulch: 100 × 0.25 ÷ 27 = 0.93 cubic yards, which you round up to 1 yard. The calculator does the same sum, then adds your allowance.
How many bags of mulch are in a cubic yard?
A cubic yard is 27 cubic feet, so divide 27 by the bag size: 13.5 bags of 2 cubic feet, or 9 bags of 3 cubic feet. Texas A&M AgriLife Extension works one cubic yard out as 14 bags of 2 cubic feet once you round up. Check the bag, because sizes vary by product and store.
How many tons of gravel are in a cubic yard?
It depends on the stone. Nevada DOT’s weight table lists loose, dry gravel at 2,565 lb per cubic yard (1.28 tons), crushed limestone at 2,625 lb (1.31 tons), crushed granite at 2,778 lb (1.39 tons) and pit-run gravel at 3,240 lb (1.62 tons). The DOT says these are for estimating only. Wet sand, for example, is listed at 3,500 lb per cubic yard against 2,700 dry.
How much extra gravel should I order?
The calculator starts with a 10% allowance, which is our planning default, not a published figure. Gravel settles and compacts under a plate compactor or traffic, and a base prepared to a firm depth takes more material than a loose-fill estimate. Penn State’s Center for Dirt and Gravel Road Studies offers separate loose and compacted conversion factors for this reason. Ask your supplier how they convert yards to tons for the stone you are buying.
How deep should mulch be?
Scotts says a 2 inch layer creates a weed barrier on its Nature Scapes mulch, and Texas A&M AgriLife Extension’s worked example uses 3 inches. Follow the product’s label. The calculator accepts any depth, so run it at 2 and at 3 inches to see the difference in bags.
Why are there no tons for mulch and topsoil?
Both are sold by volume, and their weight changes a lot with moisture, so we do not publish a density for them. The calculator gives cubic yards and bags, which is how they are bought. If your supplier sells topsoil by the ton, ask them for the weight per cubic yard.
How many square feet does a cubic yard cover?
Divide 324 by the depth in inches: 324 square feet at 1 inch, 162 at 2 inches, 108 at 3 inches, 81 at 4 inches and 54 at 6 inches. The 324 is 27 cubic feet times 12 inches per foot.
Can I use this for sand, pea gravel or crushed stone?
Yes. The material menu includes crushed limestone, crushed granite, pit-run gravel and dry sand with their DOT weights. For any other stone, choose the closest match for tons, or use cubic yards and ask your supplier for the tons per cubic yard.
Sources
- Texas A&M AgriLife Extension, Travis County: How Much Compost, Soil or Mulch? (formula, 27 cubic feet per yard, bags) (travis-tx.tamu.edu) Accessed 2026-11-13.
- Nevada Department of Transportation, Table A.2-8: weights of aggregates and sand (lb per cubic yard) (dot.nv.gov) Accessed 2026-11-13.
- NIST SP 811, Appendix B.8: ton, short = 2000 lb (nist.gov) Accessed 2026-11-13.
- ScottsMiracle-Gro, Scotts Nature Scapes Triple Shred Mulch: 2 inch weed-barrier rate (scottsmiraclegro.com) Accessed 2026-11-13.
- Penn State Center for Dirt and Gravel Road Studies, DGLVR Materials Calculator (loose and compacted conversion factors vary by region and supplier) (dirtandgravel.psu.edu) Accessed 2026-11-13.