Mulch Calculator
Buying mulch in bags or by the cubic yard? Use this free mulch calculator to work out exactly how much mulch you need for a bed, border or playground. Enter the length, width and depth in inches to get cubic yards, tons and the number of bags, plus an estimated cost.
Need a different material? Try the Topsoil Calculator, the Dirt Calculator or the main Cubic Yard Calculator.
Use this if you already know the square footage — for example from a listing, a plan, or a measuring app.
Most mulch and topsoil beds need 2–3 inches; gravel driveways 4–6 inches.
The material sets the weight and bag estimate — densities are typical averages.
Most rocks and soils fall between 2,200 and 3,000 lb per cubic yard.
Add your supplier’s price to see the estimated total cost.
Order tip: add 5–10% extra for waste, spillage and compaction — material settles once it is spread and rained on. The suggested order amount above already includes a 10% allowance, rounded up to the nearest half yard.
How to Calculate Mulch in Cubic Yards
Measure the length and width of the bed in feet and the mulch depth in inches, then work it out in three steps:
- Turn the depth into feet: depth in inches ÷ 12. For example, 3 inches is 3 ÷ 12 = 0.25 feet.
- Find the volume in cubic feet: length × width × depth in feet.
- Convert to cubic yards: divide the cubic feet by 27, because one cubic yard holds 27 cubic feet.
Formula: Cubic yards = (length in feet × width in feet × depth in inches ÷ 12) ÷ 27.
Example: A bed 12 feet long, 4 feet wide and 3 inches deep needs 0.44 cubic yards:
- Depth in feet: 3 ÷ 12 = 0.25 feet.
- Volume in cubic feet: 12 × 4 × 0.25 = 12 cubic feet.
- Cubic yards: 12 ÷ 27 = 0.44 cubic yards.
- Bags: 12 ÷ 2 = 6 bags of 2 cu ft.
- Weight: 0.44 × 600 ≈ 267 pounds.
Mulch Coverage Chart
One cubic yard of mulch covers this much area at each depth:
| Depth | Area covered by 1 cubic yard |
|---|---|
| 1 inch | 324 square feet |
| 2 inches | 162 square feet |
| 3 inches | 108 square feet |
| 4 inches | 81 square feet |
| 6 inches | 54 square feet |
As a rule of thumb, one cubic yard covers about 100 square feet at 3 inches deep — the standard depth for garden beds.
How Many Bags of Mulch Are in a Cubic Yard?
A bag is rated in cubic feet — a cubic yard holds 27 cubic feet, so divide 27 by the bag size to get the number of bags per yard:
| Bag size | Bags per cubic yard |
|---|---|
| 1.5 cu ft | 18 |
| 2 cu ft | 14 (13.5) |
| 3 cu ft | 9 |
How Much Does a Cubic Yard of Mulch Weigh?
A cubic yard of mulch weighs about 600 pounds, or 0.30 ton. Wet mulch can weigh more after rain, so leave a margin when you are loading a trailer or a truck bed.
Most half-ton pickup trucks carry 2 to 3 cubic yards of mulch per load.
Mulch Depth Guide
- Garden beds and borders: 2–3 inches.
- New beds and weed suppression: 3–4 inches.
- Trees and shrubs: 2–3 inches, kept clear of the trunk.
- Playgrounds: 9–12 inches of loose fill.
Do not pile mulch against tree trunks or plant stems — leave a gap so air can reach the bark.
Frequently Asked Questions
How many bags of mulch do I need?
Work out your volume in cubic yards, then multiply by 13.5 for 2 cu ft bags. One cubic yard needs 14 bags (13.5, rounded up), 2 cubic yards need 27 bags and 5 cubic yards need 68 bags.
How much mulch do I need for a 10×10 area?
At 3 inches deep, a 10 ft × 10 ft bed needs 0.93 cubic yards — order 1 yard in bulk or 13 bags of 2 cu ft. At 2 inches it is 0.62 yards (9 bags), and at 4 inches it is 1.23 yards (17 bags).
How deep should mulch be?
Two to three inches is right for most garden beds and borders. New beds benefit from 3–4 inches, and playground areas need 9–12 inches of loose fill. Do not pile mulch against trunks or plant stems.
How much does a cubic yard of mulch cover?
About 108 square feet at 3 inches deep, 324 square feet at 1 inch and 54 square feet at 6 inches.
More calculators: Dirt Calculator, Topsoil Calculator and the main Cubic Yard Calculator.