Mulch Calculator
Find how much mulch you need in cubic yards, cubic feet, and 2 cu ft bags from your bed size and the depth you want.
What your result means
Mulch needed is the volume to fill your bed at the chosen depth, in cubic yards (how bulk mulch is sold) and cubic feet. Bags is the count of standard 2 cubic foot bags. Bulk by the yard is cheaper once you need more than about 10-12 bags. Need the bed area first? Use our square footage calculator.
How to use this calculator
- Measure the bed length and width in feet.
- Pick a depth — 2 to 3 inches is standard for most beds.
- Read the cubic yards, cubic feet, and bag count.
- Order by the yard if you need more than 10-12 bags.
- For odd beds, split into rectangles and add the areas.
The formula
Depth converts from inches to feet by dividing by twelve. Length times width times that depth gives cubic feet; divide by 27 for cubic yards. A standard mulch bag holds 2 cubic feet.
Worked example
A 20 by 10 ft bed is 200 square feet. At 3 inches deep that's 200 × 0.25 = 50 cubic feet, or about 1.85 cubic yards. That's roughly 25 of the 2 cubic foot bags — at that point, bulk by the yard is cheaper.
Mulch depth guide
| Use | Recommended depth |
|---|---|
| Annual flower beds | 1 - 2 in |
| Shrub & perennial beds | 2 - 3 in |
| Around trees | 3 - 4 in (not on trunk) |
| Weed suppression | 3 in |
| Bag size | 2 cu ft per bag |
Tips & gotchas
- Don't pile mulch against trunks or stems — keep a few inches clear to prevent rot.
- Bulk mulch by the cubic yard beats bags once you pass roughly a dozen bags.
- One cubic yard covers about 100 sq ft at 3 inches deep.
- Refresh, don't rebuild — top up existing beds an inch rather than piling on.
- Order about 5% extra to cover settling and uneven ground.
Frequently asked questions
How much mulch do I need?
Multiply bed area by depth in feet for cubic feet, then divide by 27 for cubic yards. A 200 sq ft bed at 3 inches needs about 1.85 cubic yards.
How many bags of mulch in a cubic yard?
About 13.5 bags, since a cubic yard is 27 cubic feet and standard bags hold 2 cubic feet each.
How deep should mulch be?
2 to 3 inches for most beds. Too thin won't suppress weeds; too thick can suffocate roots and hold excess moisture.
Should I buy bags or bulk?
Bags suit small beds. Once you need more than about a dozen, bulk by the cubic yard is cheaper and less hauling.
How much area does a yard of mulch cover?
About 100 square feet at 3 inches deep, or 160 square feet at 2 inches.
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Estimates only — see our full disclaimer.