BuildRuler

Build & DIY estimates

Mulch calculator

Quick answer: Cubic yards of mulch = area in square feet × depth in inches ÷ 324. Example: a 200 sq ft bed at 3 inches deep needs 200 × 3 ÷ 324 = 1.85 cubic yards, which is 50 cubic feet, or 25 bags of 2 cubic feet. Most beds need 2 to 3 inches; top up 1 inch on existing mulch.

  • Manufacturer bag yields · published coverage rates
  • Updated
  • Reviewed by Alex · How we calculate

Many university extension services suggest a 2–4 inch layer for most beds.

How deep to spread

Two to three inches of mulch suppresses weeds and holds moisture; much deeper can smother roots. Keep mulch a few inches away from tree trunks and plant stems. One cubic yard covers about 108 sq ft at 3 inches, or 162 sq ft at 2 inches.

Bags or bulk

Bagged mulch usually comes in 2 cubic foot bags, so 13.5 bags make one cubic yard. Above about 3 yards, bulk delivery is usually cheaper than bags.

Frequently asked questions

How much does a 2 cu ft bag cover?

About 8 sq ft at 3 inches (24 sq ft at 1 inch).

How many bags of mulch do I need for 100 sq ft?

At 3 inches deep, about 12.5 two-cubic-foot bags.

Should I remove old mulch?

Only if it is thick or matted; otherwise top it up to the target depth.