Mulch Calculator
Enter your bed dimensions in feet (or the square footage directly), pick a depth, and see exactly how much mulch to buy — in cubic yards for bulk delivery and in 2 and 3 cubic foot bags for the home center. Add prices to compare bulk vs bagged before you order.
Mulch depth
120 sq ft at 3" deep needs
Cubic yards
1.11
Cubic feet
30
2 ft³ bags
15
3 ft³ bags
10
Coverage: 1 cubic yard of mulch covers
| Depth | Coverage per yard | Typical use |
|---|---|---|
| 2 inches | 162 sq ft | Flower beds, refresh |
| 3 inches | 108 sq ft | Standard new bed |
| 4 inches | 81 sq ft | Weed suppression, trees |
How much mulch do I need?
Worked example: a 10 ft × 12 ft bed (120 sq ft) mulched 3 inches deep needs 120 × 0.25 = 30 cubic feet, which is 30 ÷ 27 ≈ 1.11 cubic yards — or 15 bags of 2 cu ft (30 ÷ 2, rounded up). At that quantity, a bulk yard-and-a-half delivery is usually cheaper than bags.
Recommended depth by use
- Flower and perennial beds: 2–3 inches. Enough to retain moisture and suppress weeds; deeper layers can smother shallow roots and self-seeding plants.
- Around trees and shrubs: 3–4 inches in a wide, flat ring — but never against the trunk. So-called volcano mulching traps moisture against the bark and invites rot, insects and girdling roots. Keep a 3–6 inch gap.
- Paths and open areas: 3–4 inches of coarse mulch for maximum weed suppression and durability.
When to mulch: the best windows are mid-to-late spring (after the soil has warmed) and fall (to insulate roots for winter). Avoid mulching very early in spring — it keeps cold soil cold and slows growth.
Related material calculators
Working with other materials or odd-shaped beds? Use the square footage calculator to total an irregular area first, or the general cubic yard calculator for multiple areas and weight estimates. For specific materials, try the gravel calculator, soil calculator or concrete calculator — and the area calculator or paint calculator for area conversions and indoor jobs.