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Mulch Calculator

How much mulch to buy, in cubic yards or bags, for beds, borders and tree rings.

Bed
Shape
2 to 4 inches is the usual range. Topping up an old bed? Enter only the depth you're adding.
Bags and price
Bags and price
$
Leave at 0 to skip the cost estimate.
Price is
Mulch needed 0.93 cubic yards That's 25 cu ft to cover 100 sq ft at 3 in deep.

Bags

Bags
13 bags

Volume

Cubic feet
25 cu ft
Area covered
100 sq ft

Cost

How much mulch do I need?

Multiply the bed's area in square feet by the depth in inches, then divide by 324 to get cubic yards (one cubic yard covers 324 sq ft at 1 inch deep). For bags, divide the cubic feet by the bag size. A 20 × 5 ft bed at 3 inches needs 0.93 cubic yards, or 13 bags of 2 cu ft.

Worked example: a 20 × 5 ft bed, 3 inches deep

  1. Area: 20 × 5 = 100 sq ft.
  2. Cubic yards: 100 × 3 ÷ 324 = 0.93 cu yd (25 cu ft).
  3. Bags: 25 cu ft ÷ 2 cu ft per bag = 12.5, so buy 13 bags.

How far mulch goes

Area covered by one cubic yard and by one bag at common depths.

Depth1 cubic yard2 cu ft bag1.5 cu ft bag
1 in324 sq ft24 sq ft18 sq ft
2 in162 sq ft12 sq ft9 sq ft
3 in108 sq ft8 sq ft6 sq ft
4 in81 sq ft6 sq ft4.5 sq ft

A cubic yard is 27 cu ft: 13.5 bags of 2 cu ft, or 18 bags of 1.5 cu ft.

How deep should mulch be?

University extension services recommend 2 to 4 inches. Finer mulch can go on thinner; coarse bark chips can go nearer 4 inches. More than 4 inches can mat down, keep air and water from reaching roots, and cause problems for trees.

  • Keep mulch off trunks. Piling it against a tree (a "mulch volcano") softens bark and invites rot, insects and girdling roots. Leave a gap of a few inches around the trunk.
  • Topping up? Check how much is left first. Old mulch breaks down, but if there are already 2 inches, add only an inch or two.
  • It settles. Fresh mulch compresses over the first weeks, so it may look a little deeper on day one.

Bags or bulk

Bags are tidy and easy for small beds. For a whole yard, bulk mulch by the cubic yard is usually much cheaper: one cubic yard equals about 13 to 14 bags of 2 cu ft. Many landscape yards deliver, or a pickup can carry a yard or two of light mulch.

Frequently asked questions

How many bags of mulch are in a yard?
13.5 bags of 2 cu ft, 18 bags of 1.5 cu ft, or 9 bags of 3 cu ft. A cubic yard is 27 cubic feet.
How much area does a yard of mulch cover?
162 sq ft at 2 inches deep, 108 sq ft at 3 inches, and 81 sq ft at 4 inches.
How much does a 2 cu ft bag of mulch cover?
12 sq ft at 2 inches deep, 8 sq ft at 3 inches, or 6 sq ft at 4 inches.
How many bags of mulch do I need for a 10 × 10 bed?
100 sq ft at 3 inches is 25 cu ft: 13 bags of 2 cu ft or 17 bags of 1.5 cu ft.
How thick should mulch be around trees?
2 to 4 inches, spread in a wide ring, and kept a few inches away from the trunk. Never pile it up against the bark.

Guides

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Sources and method

Last checked October 12, 2026. How we build and test every calculator: methodology.