How the number is worked out
Area times depth gives cubic feet, divided by 27 gives cubic yards. Depth is the part people get wrong: 3 inches is 0.25 ft, so a 200 square foot bed at 3 inches is 50 cubic feet, which is under two yards. Each bed is measured on its own and added up.
area (ft²) × depth (ft) ÷ 27 = cubic yards
How deep to spread it
Two to three inches over a planted bed, three to four around trees and shrubs where you want the ground to stay damp. Deeper than four inches and you start starving roots of air rather than protecting them. Keep it pulled back a hand’s width from any trunk or stem — mulch heaped against bark holds water there and rots it.
Bulk or bags
One cubic yard is thirteen and a half of the standard two-cubic-foot bags. The ticket rounds up to whole bags and compares the material prices you enter. Delivery fees, minimum orders, vehicle capacity and handling can change the final cost; no fixed bag count determines the cheaper option.
Topping up an old bed
An established bed does not need the full depth again. Rake what is there to break the crust, then add an inch — that is a third of a new bed, and it is the number most people over-order. Measure the beds, set the depth to 1 inch, and read the ticket.
What one cubic yard covers
| Depth | Coverage | In 2 ft³ bags | Typical use |
|---|
| 1 in | 324 ft² | 13.5 | topping up an established bed |
| 2 in | 162 ft² | 13.5 | annual beds and borders |
| 3 in | 108 ft² | 13.5 | new beds, weed suppression |
| 4 in | 81 ft² | 13.5 | around trees and shrubs |
Questions
How many bags of mulch are in a cubic yard?
Thirteen and a half of the standard two-cubic-foot bags, eighteen of the 1.5 cubic foot bags, or nine of the three-cubic-foot bags. Most people round up to fourteen.
How much does a yard of mulch weigh?
Four hundred to eight hundred pounds dry for shredded bark, and closer to a thousand after rain. A half-ton pickup carries the weight of two yards easily but not the bulk — a yard heaped is about the size of a washing machine.
How deep should mulch be?
Three inches is the working answer for a new bed: enough to hold moisture and stop weed seed, not so much that it suffocates roots. An inch is plenty when you are refreshing.
Should I add extra for settling?
No. Mulch is measured at the depth you want to see, and it settles into the soil rather than shrinking away from it. The allowance here starts at zero on purpose; the honest extra is the inch you add next spring, not a percentage today.
Does mulch stop weeds?
Three inches stops most weed seed from germinating, because seed needs light. It will not stop anything already rooted underneath — that has to come out first.
Other calculators
The same ticket, the same assumptions on screen, for whatever else the job needs.
Concrete slabs, footings, columns and stepsGravel driveways, bases and drainage stoneRiver rock beds, borders and dry creeks, by stone sizeAsphalt hot mix by the tonTopsoil beds, lawns and levellingFill dirt holes, grades and backfill, with settlingSand paver bedding, play sand and fillCubic yards any volume, in every unitRebar bars, sticks, laps and weight