Last updated: October 2026
How much mulch do I need?
Short answer: Multiply bed length × width × (depth in inches ÷ 12) to get cubic feet, then divide by 27 for cubic yards. One cubic yard covers about 100 sq ft at the standard 3-inch depth. The calculator above converts your bed to cubic yards and bag count automatically.
How to measure a mulch bed
Measure the length × width of each bed in feet. For irregular or curved beds, split them into rough rectangles (or triangles, halved) and add them up — mulch is forgiving, and a 5% waste allowance covers the overlap. The standard depth is 3 inches: enough to block weeds and hold moisture without smothering roots.
Mulch depth guide
| Depth | Best for | Coverage per cubic yard |
|---|---|---|
| 2 inches | Touch-ups over existing mulch | ≈ 162 sq ft |
| 3 inches | New beds, flower and garden beds (standard) | ≈ 108 sq ft |
| 4 inches | Weed-heavy areas, playground surfaces | ≈ 81 sq ft |
Bags vs bulk: which is cheaper?
Bags (usually 2 or 3 cu ft) are easy to carry and stack, but cost more per yard — one cubic yard equals 13.5 two-cubic-foot bags. Bulk mulch by the cubic yard from a landscape supplier is typically much cheaper per yard, but you need a driveway spot for the delivery truck. As a rough rule, bulk usually wins above 2–3 cubic yards. Enter both prices in the calculator to compare exactly.
Frequently asked questions
How much mulch do I need?
Multiply bed length × width × (depth in inches ÷ 12) to get cubic feet, then divide by 27 for cubic yards. As a rule of thumb: one cubic yard of mulch covers about 100 square feet at 3 inches deep. The calculator above does the math and converts it to bags.
How deep should mulch be?
3 inches is the standard depth for mulch around plants and beds — deep enough to suppress weeds and hold moisture, shallow enough to let water reach the roots. Use 4 inches for weed-heavy areas and 2 inches for touch-ups on existing mulch. Read about mulch types and their benefits before you buy.
How many bags of mulch do I need?
Divide your total cubic feet (including waste) by the bag size and round up. One cubic yard equals 13.5 two-cubic-foot bags or 9 three-cubic-foot bags. The calculator above gives the exact bag count for your bed.
Should I buy mulch in bags or bulk?
Bags are easier for small beds and cost more per cubic yard; bulk (by the cubic yard from a landscape supplier) is cheaper for large areas but you need a driveway spot for delivery. Compare both prices in the calculator — as a rough guide, bulk usually wins above 2–3 cubic yards.
How much does a cubic yard of mulch cover?
One cubic yard covers about 324 square feet at 1 inch deep, 162 square feet at 2 inches, and 108 square feet at 3 inches. For 2-cubic-foot bags, one cubic yard equals 13.5 bags.
Is my project data private?
Completely. Every calculation runs locally in your browser with JavaScript — your measurements are never sent to a server, stored, or tracked.