Mulch Calculator
Bags or bulk, and the depth that decides which is cheaper.
Work out Mulch. Bags or bulk, and the depth that decides which is cheaper. Free, with no account and nothing to download.
Bark mulch runs 0.4–0.5 tons per cubic yard — far lighter than stone.
A standard bag is 2 cubic feet. Set to zero for bulk.
Density varies with material, stone size and how wet it is, and you are charged for what crosses the weighbridge. Use the supplier's own figure rather than a general one — it moves the tonnage proportionally.
Cubic yards needed
4.63
2.08 tons · 125.0 cu ft
4.63 cubic yards, or 63 bags at the size entered. A cubic yard is 27 cubic feet, so it is about fourteen two-cubic-foot bags — past a couple of yards, bulk delivery is normally cheaper even after the delivery charge.
How the Mulch Calculator works
Mulch is sold two ways and the crossover is worth knowing: bags are convenient up to a point, and bulk by the cubic yard is dramatically cheaper past it. Since a cubic yard is twenty-seven cubic feet and a typical bag holds two, one yard is around fourteen bags — which is usually where hauling bags stops making sense.
Also known as: how much mulch do I need · mulch calculator bags · bark mulch calculator · cubic yards of mulch
The calculation itself
Bed area times depth in inches, divided by twelve for cubic feet, then by twenty-seven for cubic yards — or by the bag volume for a bag count.
Mulch is far lighter than stone: bark runs around 0.4 to 0.5 tons per cubic yard against 1.4 for gravel. That is why density is a separate input rather than shared with the aggregate tools.
In practice
500 square feet at three inches is 125 cubic feet, or 4.63 cubic yards. In two-cubic-foot bags that is 63 bags.
Sixty-three bags is the number that settles the bags-versus-bulk question. A cubic yard is 27 cubic feet, so it is about fourteen bags — and past a couple of yards, bulk delivery is normally cheaper even once the delivery charge is counted, before you consider the hauling.
Depth is the lever. Dropping from three inches to two takes the same bed from 63 bags to 42, which is often the difference between a car boot and a truck.
Where the figure deceives
It assumes an empty bed. Most beds are being topped up rather than filled, and organic mulch breaks down by an inch or two a year — so measuring what is already there first avoids ordering for depth you already have.
Deeper is not better. Past three inches mulch can starve roots of air, and piling it against trunks causes rot. The commonest mulching mistake is depth rather than quantity, and this calculator will happily compute a bad idea.
Bag volumes vary by brand and by whether the material is compressed. The bag size is an input for that reason — check the bag rather than assuming two cubic feet.
Acting on it
Measure the existing depth before ordering a top-up, and buy the difference rather than the full depth.
Work out the bag count and the bulk yardage both, then compare delivered prices. The crossover is usually around two to three yards.
Keep mulch clear of trunks and stems regardless of what the volume says.
Frequently asked questions
How much mulch do I need?
Bed area in square feet times depth in inches, divided by twelve, gives cubic feet. Divide by twenty-seven for cubic yards, or by the bag volume for a bag count.
How deep should mulch be?
Two to three inches for most beds. Deeper holds moisture better but can starve roots of air, and piling it against trunks causes rot — the common mistake is depth rather than quantity.
How many bags in a cubic yard?
About fourteen at two cubic feet a bag, or roughly thirteen and a half at the same size. Past a couple of yards, bulk delivery is normally cheaper even after the delivery charge.
How often does mulch need topping up?
Organic mulch breaks down and typically needs an inch or two annually rather than a full replacement. Measuring the existing depth first avoids ordering for a bed that is already half full.
Does mulch weigh much?
Far less than aggregate — around 0.4 to 0.5 tons per cubic yard for bark, against 1.4 for gravel. That is why the density is an input rather than shared with the stone calculators.
Put this calculator on your own site
Free to use, on any site, commercial or not. Paste this where you want it to appear. It is a plain iframe, so it works in WordPress, Squarespace, Wix, Webflow, Ghost and anything else that accepts HTML.
<iframe src="https://www.thecalclibrary.com/embed/mulch-calculator" width="100%" height="640" style="border:1px solid #e2e8f0;border-radius:12px" loading="lazy" title="Mulch Calculator"></iframe>The only condition is that the credit line stays visible. It sits inside the frame, so you do not have to do anything to keep it.