How Much Gravel or Mulch Do I Need?
Landscape materials are sold by the cubic yard, by the ton or in bags, which makes ordering confusing. This gravel and mulch calculator converts your area into cubic feet, cubic yards, tons and 40 lb bags. Enter the length, width and depth, then choose a material: gravel, wood mulch, sand or topsoil. Each material has its own typical weight per cubic yard.
How It Is Calculated
Cubic feet = length (ft) × width (ft) × depth (in ÷ 12). Cubic yards = cubic feet ÷ 27. Tons = cubic yards × material density. Bags = tons × 2,000 ÷ 40.
Typical densities used: gravel 1.40 tons per cubic yard, sand 1.35, topsoil 1.10 and wood mulch 0.40.
Example: a 20 ft × 20 ft area covered 3 inches deep needs 100 cubic feet, or 3.7 cubic yards. In gravel, that is about 5.2 tons or 260 bags of 40 lb.
Recommended Depths
- Mulch for garden beds: 2–3 inches.
- Decorative gravel or pea gravel paths: 2–3 inches.
- Gravel driveways: 4–6 inches over a compacted base.
- Topsoil for new lawns: 4–6 inches.
- Sand base for pavers: about 1 inch over a gravel base.
Frequently Asked Questions
Is it cheaper to buy gravel in bulk or in bags?
For anything more than about 1 cubic yard, bulk delivery is usually much cheaper per yard. Bags are convenient for small beds and touch-ups.
How many bags of mulch are in a cubic yard?
Mulch is often sold in 2 cubic foot bags, so it takes 13.5 bags to make one cubic yard (27 ÷ 2). Check the bag size, because 1.5 and 3 cubic foot bags are also common.
Why does the weight vary between materials?
Materials have different densities. A cubic yard of gravel weighs about 1.4 tons, while the same volume of wood mulch weighs only about 0.4 tons. Moisture also affects weight.