ContractorHandbook

How Much Mulch for 100 Square Feet?

Material needed

0.93 cubic yards

100 square feet at 3 inches deep, bark mulch at roughly 800 lb per cubic yard.

It does not stop at a number.

When the figures look right, the landscape material list downloads as a real PDF with your business details on it, built inside your own browser. Nothing you type is uploaded anywhere.

bed length, ftdepth, inbed width, ftarea x (depth in inches / 12) / 27 = cubic yards
Three inches is the working depth for mulch, and depth is the input people guess at. Bulk comes by the yard and bags hold two cubic feet, so the same volume answers both questions.

How that number is worked out

These are the figures this page was built with and every line the calculator produces from them. Change anything above and all of it moves.

  • Bed area100 sq ft
  • Depth3 in
  • MaterialMulch

Material needed0.93 cubic yards

Volume25 cu ft
Cubic yards0.93most yards sell in half yard steps
Order in half yards1 cu yd
2 cu ft bags, if bagging it13
Approximate weight741 lb (0.37 tons)

The material list this produces

Material, cubic yards1
Landscape fabric, sq ft100
Edging, linear ft40

Depth compared

Depth is the whole calculation. Two inches will not suppress weeds, six inches will suffocate roots.

DepthMaterial neededOrder in half yards
2 in0.62 cubic yards1 cu yd
3 in0.93 cubic yards1 cu yd
4 in1.23 cubic yards1.5 cu yd
6 in1.85 cubic yards2 cu yd

What else matters here

A hundred square feet at three inches is just under a cubic yard, which is the crossover point where bags stop making sense. Thirteen bags at typical retail is usually more than a yard delivered, and it is thirteen bags to carry, open and dispose of.

If you do bag it, check the bag size. Two cubic feet is the common one but three cubic foot bags exist and one and a half is sold too, so the bag count on a shelf tag is not comparable between brands without doing the volume.

Three inches is the working depth for weed suppression. Less than two and light reaches the soil and the weeds come anyway; more than four and you start holding water against stems and starving roots of air.

What this calculator assumes

  • Three inches is the usual mulch depth. Two is thin and will not hold weeds down, four starts to smother shallow roots and holds water against trunks.
  • Weights are approximate and vary with moisture: mulch about 800 lb per cubic yard, topsoil 2200, gravel 2800, sand 2700.
  • Bagged material is sold in 2 cubic foot bags, and there are 13.5 of those in a cubic yard.

Questions people ask

How many bags of mulch for 100 square feet?

About 13 bags at 2 cubic feet each for a 3 inch depth, or just under one cubic yard in bulk.

Is bagged or bulk mulch cheaper?

Bulk is almost always cheaper per cubic yard once you need a yard or more. Below that, delivery fees usually make bags the practical choice.

How deep should mulch be?

Three inches for most beds. Two is not enough to stop weeds and more than four holds moisture against stems and can starve roots of air.

Different numbers?

The mulch and gravel calculator takes any dimensions you like and hands back the same list.

Other common sizes