Mulch Calculator
Enter your space and we’ll estimate how much mulch to buy.
How we measure depth
We measure the average depth of the mulch after it’s spread and fluffed, not the depth of the pile. For a new bed use 3 inches; for an annual refresh over old mulch, 1–2 inches is plenty.
How we calculated it
Mulch is sold by volume, so we turn your bed into cubic feet: length × width × depth (converted to feet). We add your waste allowance, divide by the bag size you’re buying, and round up to whole bags. We also show cubic yards in case bulk delivery is cheaper.
Things that can change your result
- Depth is the decision that moves the number most — 2″ refresh vs. 3″ new bed is a 50% difference.
- Irregular, curvy beds hold more mulch than a clean rectangle suggests — round your measurements up.
- Fluffed mulch settles about 20% in the first weeks; the waste allowance covers this.
Buying tips
- Above roughly 2 cubic yards (about 27 two-cubic-foot bags), bulk delivery usually beats bags on price.
- Buy a bag or two extra for the annual top-up — unopened bags keep fine in a dry corner.
- Keep mulch a couple of inches away from trunks and stems — volcano mulching harms trees.
Common mistakes
- Measuring the pile, not the spread depth.
- Forgetting that beds with curves and islands add up to more area than they look.
- Buying exactly the calculated amount with no allowance — the last corner always runs short.
Frequently asked questions
How many bags of mulch are in a cubic yard?
A cubic yard is 27 cubic feet — that’s 13.5 two-cubic-foot bags, or 18 bags at 1.5 cubic feet.
Should I buy bags or bulk?
Rule of thumb: under about 1 cubic yard, bags are easier; over 2 yards, bulk delivery is usually cheaper. In between, compare the delivery fee against the bag premium.
How deep should mulch be?
Around 3 inches for a new bed — enough to suppress weeds without smothering roots. Use 1–2 inches when refreshing over existing mulch.