Mulch Calculator
Enter the size of your beds or tree rings and the depth to get the mulch in cubic yards and in 2 or 3 cubic foot bags, rounded up to what you buy.
In feet. For 10 ft 6 in, enter 10.5.
Clemson Extension: no more than 2 to 3 inches of fine wood or bark mulch, up to 4 of coarse bark nuggets, and no more than 2 of grass clippings or leaves.
For 5 trees with the same ring, enter 5.
Bags are already rounded up. Enter a percent if you want more on hand.
Mulch you need
0.74 cubic yards
Buy 10 bags of 2 cu ft or 7 bags of 3 cu ft. In bulk, order 1 cubic yard. Both are rounded up, so a little is left over.
| One bed: 20 ft × 4 ft | 80 sq ft |
|---|---|
| Mulch to spread: × 3 in deep (÷ 12 = 0.25 ft) | 20 ft³ |
| ÷ 27 cubic feet in a cubic yard | 0.74 yd³ |
| Bag | One bag covers | Bags you need |
|---|---|---|
| 1.5 cu ft | 6 sq ft | 14 |
| 2 cu ft | 8 sq ft | 10 |
| 3 cu ft | 12 sq ft | 7 |
The bag size in cubic feet is printed on the bag. Bag counts are rounded up to whole bags.
How this is calculated
Mulch is area × depth, with the depth in inches divided by 12. A bed 20 ft long and 4 ft wide, 3 inches deep, takes 80 × 3 ÷ 12 = 20 cubic feet. That is 20 ÷ 27 = 0.74 cubic yards, or 10 bags of 2 cubic feet, or 7 bags of 3 cubic feet (6.67, rounded up).
A ring around a tree is a circle: π × (diameter ÷ 2)². A ring 6 ft across is 3.1416 × 3² = 28.27 square feet. Five such rings, 3 inches deep, take 5 × 28.27 × 0.25 = 35.34 cubic feet, or 18 bags of 2 cubic feet.
How far a cubic yard and a bag go
| Depth | 1 cubic yard | Bag of 2 cu ft | Bag of 3 cu ft |
|---|---|---|---|
| 1 in | 324 sq ft | 24 sq ft | 36 sq ft |
| 2 in | 162 sq ft | 12 sq ft | 18 sq ft |
| 3 in | 108 sq ft | 8 sq ft | 12 sq ft |
| 4 in | 81 sq ft | 6 sq ft | 9 sq ft |
Clemson Extension puts it the same way: one cubic yard covers 324 square feet with an inch of mulch. Mulch is sold by volume, in cubic yards or cubic feet (NIST Handbook 130), so the bag size in cubic feet is on every bag. Bag counts are rounded up to whole bags, and bulk mulch to the next half cubic yard.
How deep to spread mulch
- Penn State Extension: 2 to 4 inches of organic mulch around trees and no more, less on poorly drained soil, and 1 to 2 inches of fine or double-shredded mulch.
- Clemson Extension: no more than 2 to 3 inches of fine wood and bark mulch, up to 4 inches of coarse mulch such as pine bark nuggets, 2 to 3 inches of pine straw, and never more than 2 inches of grass clippings or shredded leaves.
- Penn State Extension: keep mulch off the trunk, 3 to 5 inches away from young trees and 8 to 10 inches from mature trees.
For stone instead of mulch, the gravel calculator works out tons.
Sources
Checked against the sources below on .
Questions people ask
How many bags of mulch are in a yard?
13.5 bags of 2 cubic feet, so 14 bags, because a cubic yard is 27 cubic feet. It takes 9 bags of 3 cubic feet.
How much does a 2 cubic foot bag of mulch cover?
12 square feet 2 inches deep, 8 square feet 3 inches deep, and 6 square feet 4 inches deep. A 3 cubic foot bag covers 18, 12 and 9 square feet.
How deep should mulch be?
Penn State Extension advises 2 to 4 inches of organic mulch around trees and no more, or 1 to 2 inches of fine or double-shredded mulch. Clemson Extension puts fine wood and bark mulch at no more than 2 to 3 inches.
How much area does a yard of mulch cover?
324 square feet 1 inch deep, according to Clemson Extension. At 2 inches that is 162 square feet, and at 3 inches 108 square feet.
How much mulch do I need for 200 square feet?
At 3 inches deep, 200 square feet takes 50 cubic feet, or 1.85 cubic yards: 25 bags of 2 cubic feet or 17 bags of 3 cubic feet.
How far from a tree should mulch be?
Penn State Extension says to pull mulch 3 to 5 inches away from young trees and 8 to 10 inches away from mature trees.