Mulch Calculator — How Much Mulch Do I Need?
Enter your garden bed's area and your target depth to get the exact amount of mulch in cubic yards and bags. No sign-up, no data stored.
Mulch needed
How mulch quantity is calculated
The math is simple and exact — no assumptions to adjust for:
- Area = length × width (in square feet).
- Volume = area × depth in inches ÷ 12 (this converts inches to feet).
- Cubic yards = volume ÷ 27 (there are 27 cubic feet in a cubic yard).
- Bags = volume ÷ bag size (a standard bag is 2 cubic feet), rounded up.
- Cost = cubic yards × price per cubic yard (only if you enter a price).
Mulch settles a little over time, so ordering about 10% more than the exact number is common, especially for new beds.
Mulch coverage chart
How far a cubic yard of mulch goes at common depths, and how bags add up.
Coverage per cubic yard
| Depth | Sq ft covered by 1 cu yd |
|---|---|
| 1 inch | ~324 sq ft |
| 2 inches | ~162 sq ft |
| 3 inches | ~108 sq ft |
| 4 inches | ~81 sq ft |
Bags per cubic yard
| Bag size | Bags in 1 cu yd |
|---|---|
| 1.5 cu ft | 18 bags |
| 2 cu ft | 13.5 bags |
| 3 cu ft | 9 bags |
Last updated: October 2026 · Depth guidance reflects common landscaping practice. Bulk prices vary by region and material; the cost line is an estimate based on the price you enter.
Mulch calculator FAQ
At 100 sq ft and 2 inches deep, you need 100 × (2 ÷ 12) = 16.7 cubic feet, which is about 0.6 cubic yards or 9 bags of 2-cubic-foot mulch.
Bulk (by the cubic yard) is cheaper for anything larger than a few beds, but you pay for delivery or hauling. Bags are convenient for small areas and let you spread by hand with no equipment.
Yes. More than 3–4 inches can trap moisture against tree trunks and roots, cause rot, and invite pests. Keep 2–3 inches and pull mulch a few inches away from trunks and stems.
Yes, mulch compacts and settles as it breaks down, often losing some depth over the season. Ordering 10% more than the exact amount is a common buffer for new beds.
Mulch is applied on top of the soil to retain moisture and suppress weeds, while compost is worked into the soil to improve fertility. You can use compost as a thin mulch, but it's mainly an amendment.
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