Mulch Calculator: How Much Mulch Do You Need?
A free mulch calculator that tells you how many cubic yards of mulch your project needs, how many bags of mulch you need in 2 and 3 cu ft sizes, and what it will cost. No sign-up, everything happens in your browser.
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How to measure for mulch
- Measure the bed. For a rectangle, pace or tape the length and width in feet. For a round bed, measure across the widest point to get the diameter. Ignore curves and odd edges at first; you can add 10 percent for irregular shapes.
- Choose your depth. Match the depth to what you are mulching: flower beds, trees, or playground areas. The table below has common recommendations.
- Order a little extra. Mulch settles and compacted beds are rarely perfectly flat. Rounding up to the nearest half yard, or adding about 10 percent, saves a second trip.
Mulch depth recommendations
| Project | Suggested depth |
|---|---|
| Flower and garden beds | 2 to 3 inches |
| Trees and shrubs | 3 to 4 inches |
| Vegetable gardens | 2 to 3 inches |
| Playgrounds (loose-fill) | 6 to 9 inches |
| Pathways | 2 to 4 inches |
Keep mulch 2 to 3 inches away from tree trunks and plant stems to prevent rot.
Mulch calculator questions
How deep should mulch be?
Most garden and flower beds do best with 2 to 3 inches of mulch. Around trees and shrubs, go 3 to 4 inches deep, but keep the mulch pulled back a few inches from the trunk. Playgrounds using loose-fill mulch need a much deeper layer, typically 6 to 9 inches, for safe cushioning under play equipment.
How often should I re-mulch?
Plan to top up mulch once a year, usually in spring. Organic mulch breaks down as it feeds the soil, so check bed depth each season. If it has thinned below your target, add enough fresh mulch to restore it rather than piling on a full new layer every time.
Should I use mulch or topsoil?
Mulch and topsoil do different jobs. Topsoil is growing medium: you use it to raise a bed, fill low spots, or give plants roots something to grow in. Mulch sits on top of the soil to hold in moisture, block weeds, and regulate soil temperature. For a new bed, add topsoil first, then finish with mulch over it.