Mulch Calculator

How much mulch do I need?

The amount of mulch you need is the area you want to cover multiplied by the depth of the mulch layer. This mulch calculator—also a mulch estimator and cubic yard calculator for landscaping—does that math for you in cubic yards, cubic feet, cubic meters, and liters, tells you how many bags of mulch to buy, and estimates the cost if you enter a price.

Enter the total square footage of your beds, or switch to length × width and add up to 12 separate rectangular areas. You can mix units: feet, inches, yards, meters, or centimeters for the areas, and inches, centimeters, feet, yards, or meters for the depth.

Mulch formula: cubic yards of mulch

cubic yards = area (sq ft) × depth (in) ÷ 324

One cubic yard holds 27 cubic feet, and a 1-inch layer is 1/12 of a foot, so one cubic yard of mulch covers 27 × 12 = 324 square feet at 1 inch deep. At 3 inches deep, the same cubic yard covers 108 square feet—about a 10 × 10 ft bed.

For example, a 320 sq ft bed mulched 3 inches deep needs 320 × 3 ÷ 324 ≈ 2.96 cubic yards, or 80 cubic feet. That is 40 two-cubic-foot bags or 27 three-cubic-foot bags.

How many bags of mulch do I need?

Bagged mulch is sold by volume, most often in 2 cubic foot bags in the US, with 1.5 and 3 cubic foot bags also common. Divide the cubic feet you need by the bag size and round up. The calculator lists the bag count for 1.5, 2, and 3 cu ft bags and for 60-liter bags. Because 1 cubic yard equals 13.5 two-cubic-foot bags, bulk mulch is usually cheaper once you need more than a couple of cubic yards.

How deep should mulch be?

• Garden and shrub beds: 2 to 4 inches (5 to 10 cm). Around 3 inches is a common target.
• Trees and shrubs with coarse mulch: 3 to 4 inches, pulled back a few inches from trunks and stems.
• Seedlings, small vegetables, and herbs: about 1 inch so growth is not smothered.

Mulch that is too thin lets weeds through and dries out quickly; mulch that is too thick can keep water and air from reaching the soil.

What the result includes

• The mulch volume in cubic yards, cubic feet, cubic meters, and liters.
• The total area in square feet and square meters, plus a breakdown when you enter several areas.
• The number of bags needed for common bag sizes, rounded up to whole bags.
• The estimated cost when you enter a price per cubic yard, cubic foot, cubic meter, liter, or bag.

The estimate assumes an even layer over flat ground. Fresh mulch settles over the first few weeks, so many landscapers order about 10% extra.

Frequently asked questions

How many square feet does a yard of mulch cover?

One cubic yard of mulch covers 324 sq ft at 1 inch, 162 sq ft at 2 inches, 108 sq ft at 3 inches, and 81 sq ft at 4 inches.

How many bags of mulch are in a yard?

A cubic yard is 27 cubic feet, which equals 13.5 bags of 2 cubic feet, 9 bags of 3 cubic feet, or 18 bags of 1.5 cubic feet.

How do I measure an irregular or round bed?

Split an irregular bed into rectangles and enter each one as a separate area. For a round bed, multiply the radius by itself and by 3.14 to get the square footage, then use the total area option.

Can I use this as a cubic yard calculator for soil or gravel?

Yes. The volume math—area times depth—is the same for topsoil, compost, or gravel. Only the bag counts and typical depths are specific to mulch.