Mulch Calculator
Enter each bed's length, width, and depth. Cubic yards, bag counts, and cost update as you type. Add a price per cubic yard to estimate what the mulch will cost.
| Length (ft) | Width (ft) | Depth (in) | Cu ft |
|---|
How to calculate mulch
Mulch is sold by volume, so the calculation starts with the volume of each bed: its area times how deep you're covering it. Convert everything to feet first, then to cubic yards, since that's the unit suppliers sell in.
Cubic yards is what a bulk supplier bills you for:
For bagged mulch, divide the cubic feet you need by the bag size and round up. You can't buy a fraction of a bag.
Coverage per cubic yard
A cubic yard covers less ground as you go deeper, since the same 27 cubic feet gets spread thinner.
| Depth | Coverage per cubic yard |
|---|---|
| 2 in | 162 sq ft |
| 3 in | 108 sq ft |
| 4 in | 81 sq ft |
Bags per cubic yard
Bagged mulch comes mostly in 2-cubic-foot and 3-cubic-foot sizes.
| Bag size | Bags per cubic yard |
|---|---|
| 2 cu ft | 13.5 |
| 3 cu ft | 9 |
How deep to mulch
3 inches is the working depth for most shrub and perennial beds. It suppresses weeds and holds soil moisture without smothering roots. Annual flower beds do better at 2 inches, since their roots sit closer to the surface. Anything past 4 inches starts working against the plants: water struggles to reach the soil, and roots can suffocate under the extra mass.
Keep mulch off trunks and stems. A ring of mulch piled against bark traps moisture there and invites rot and pests. Pull it back a few inches so the base of the plant stays dry.
Will a yard of mulch fit in a pickup truck?
Yes. Volume is the limit with mulch, not weight: a cubic yard of dry mulch weighs about 400 pounds, far under any pickup's payload rating, but it fills 27 cubic feet of bed space. An 8-foot full-size bed loaded level with the rails holds about 59 cubic feet after the wheel wells, or 2 cubic yards. A 6.5-foot short bed holds about 1.5 cubic yards the same way. Bring a tarp to cover the load; loose mulch blows out of an open bed at highway speed.
Bulk or bagged mulch: which costs less?
Bulk is cheaper per yard if you haul it yourself. At $45 per cubic yard bulk and $4 per 2-cubic-foot bag, a yard of bagged mulch costs $54 (13.5 bags at $4 each), so picking up bulk saves $9 a yard from the first yard on. Delivery changes the math. A $60 delivery fee spread over the order means bulk doesn't beat bags until about 7 cubic yards at those prices.
Bags still win small jobs on handling alone. They stack in a trunk, carry to the back fence one at a time, and leave no pile of loose mulch sitting on the driveway between weekends.
Frequently asked questions
How many bags of mulch are in a cubic yard?
A cubic yard holds 13.5 bags of 2-cubic-foot mulch or 9 bags of 3-cubic-foot mulch. Buy a whole bag past that fraction; a store won't sell you half of one.
How much mulch do I need for my beds?
Multiply each bed's square footage by its depth in feet, then divide by 27 to get cubic yards. This calculator runs that math for every bed you add and totals the result.
How deep should mulch be?
Most planting beds hold moisture well at 3 inches of mulch. Drop to 2 inches around annual flowers, since their roots sit shallow. Past 4 inches, mulch traps too much moisture against roots and can suffocate them. Keep mulch a few inches back from tree trunks and stems.
How much does a cubic yard of mulch cover?
One cubic yard covers 162 square feet at 2 inches deep, 108 square feet at 3 inches deep, or 81 square feet at 4 inches deep.
How much does a yard of mulch weigh?
A cubic yard of dry wood mulch weighs about 400 pounds. Wet, dense mulch can weigh 800 pounds or more. Bagged mulch lists its own weight on the label.
Should I buy extra mulch beyond the calculated amount?
Add 5 to 10 percent for uneven ground and settling, then round up to the nearest full bag or yard. Bulk suppliers rarely sell partial yards anyway.
Spreading a different material? Try the cubic yard calculator for a general volume-to-yards conversion, the topsoil calculator for garden beds, or the gravel calculator for paths and drainage. More tools are on the WeekendCalculator homepage.