Mulch Calculator
Mulch needed (cubic yards) = Area (sq ft) x Depth (inches) / 324. One cubic yard of mulch covers about 324 sq ft at 1 inch deep, 162 sq ft at 2 inches, or about 108 sq ft at 3 inches.
Quick Answer
Mulch needed (cubic yards) = Area (sq ft) x Depth (inches) / 324. One cubic yard of mulch covers about 324 sq ft at 1 inch deep, 162 sq ft at 2 inches, or about 108 sq ft at 3 inches.
Mulch Calculator
Enter the area to cover and your target depth to see how many cubic yards, cubic feet, or bags of mulch you need.
Enter your values and click calculate.
How to Use This Calculator
Multiply length by width in feet for each section, and add sections together for irregular beds.
2-3 inches is standard for most mulch; fine mulch usually stays at 1-2 in, while coarse bark or weed-suppression mulch can go 3-4 in.
Bulk mulch is sold by the cubic yard; bagged mulch is usually 2 or 3 cubic feet per bag.
Piling mulch more than about 4 inches deep, or against trunks and stems, can trap moisture and encourage rot.
Formula
Cubic feet = (Area sq ft x Depth in) / 12. Cubic yards = Cubic feet / 27.
Coverage per Cubic Yard by Depth
| Depth | Coverage per cu yd |
|---|---|
| 1 in | ~324 sq ft |
| 2 in | ~162 sq ft |
| 3 in | ~108 sq ft |
| 4 in | ~81 sq ft |
Common Mistakes to Avoid
- Mulching deeper than 3-4 inches, which can suffocate roots and encourage fungal rot, especially when piled against trunks (“mulch volcanoes”).
- Measuring depth right after delivery before it settles — loose mulch compacts over the first few weeks.
- Assuming all bags are the same size — 1, 2, and 3 cubic foot bags are all common and change your bag count significantly.
- Forgetting to account for irregular bed shapes by splitting them into simpler sections first.
When the Estimate May Be Wrong
Bulk and bagged mulch can have slightly different settled density, and organic mulch continues to compact and break down over the season, so a bed may need a top-up refresh rather than a full re-application. For large commercial jobs, order slightly over the calculated amount since suppliers can’t deliver partial cubic yards.
FAQs
How many bags of mulch are in a cubic yard?
About 13.5 bags of 2 cubic foot mulch (or 9 bags of 3 cubic foot mulch) make one cubic yard (27 cubic feet).
How deep should mulch be?
2-3 inches is the standard recommended depth for most garden beds; going much deeper risks rot and pest issues.
Is bulk mulch cheaper than bagged mulch?
For larger areas, bulk mulch delivered by the cubic yard is usually significantly cheaper per cubic foot than bagged mulch from a bag rack.
Sources and Methodology
Coverage figures (324 sq ft per cubic yard at 1 inch depth, scaling proportionally at other depths) reflect the standard mulch coverage math used across major landscaping supplier calculators and gardening references as of 2026.
