Mulch Calculator
Cubic yards & bags for beds & borders
Enter bed dimensions
New mulch: 3 in · Refresh: 1–2 in
Your results
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Formula & explanation
Bed area times depth (in inches, ÷12 to get feet) gives cubic feet. Divide by 27 for cubic yards. Bag count divides cubic feet by the bag's cubic-foot capacity. Bulk mulch sold by the cubic yard is typically cheaper for beds larger than about 3 cubic yards.
Example calculation
10 × 8 ft bed, 3 in deep, 2 cu ft bags:
Volume = 80 × 0.25 = 20 cu ft ÷ 2 = 10 bags (or 0.74 cu yd bulk).
Buying & project-planning tips
- Don't pile mulch against tree trunks ("mulch volcanoes") — it causes rot. Keep a few inches clear.
- Lay 3–4 inches for new beds; 1–2 inches to refresh existing mulch each year.
- Bulk delivery by the cubic yard is much cheaper for beds over ~3 cu yd.
- Use landscape fabric under mulch to suppress weeds — avoid plastic, which blocks water.
- Dyed mulch may need 24–48 hours to set before rain or watering.
Frequently asked questions
How deep should mulch be?+
3–4 inches for new beds to suppress weeds and retain moisture. 1–2 inches to refresh existing mulch each season — don't let total depth exceed 4 inches.
Bagged or bulk mulch?+
Bags (typically 2 cu ft) are easy for small jobs. Bulk by the cubic yard is far cheaper for beds over about 3 cubic yards and avoids plastic waste.
How many cubic feet in a cubic yard?+
27 cubic feet = 1 cubic yard. So a 2 cu ft bag holds about 0.074 cubic yards — roughly 14 bags per cubic yard.
Should I use landscape fabric under mulch?+
Yes for weed suppression — use breathable landscape fabric, not plastic. Fabric blocks weeds while letting water and air through to roots.