Mulch Calculator

What this calculator does

The Mulch Calculator estimates the volume of mulch needed to cover a garden bed, border, or landscape area at a chosen depth. It reports the volume in cubic feet, cubic yards, cubic meters, and liters, and also estimates how many bags are needed for a bag size you choose.

Mulch is usually sold in two ways: loose by the cubic yard, or bagged by the cubic foot. Bulk mulch is economical for large beds, while bags are convenient for small areas and for carrying in a passenger vehicle. The calculator shows both volume units so you can compare prices.

How to use this calculator

1. Enter the area to cover in square feet. For a rectangular bed, multiply length by width before entering the result.
2. Enter the mulch layer depth in inches. Two to four inches is a common range for weed suppression and moisture retention.
3. Enter the bag size in cubic feet. A standard bag is often 2 cubic feet.
4. Click Calculate.

The default example is 200 square feet at a 2-inch depth. It returns 33.33 cubic feet, 1.23 cubic yards, 0.94 cubic meters, about 944 liters, and 17 bags of 2-cubic-foot mulch.

Mulch formulas

volume (cu ft)  = area (sq ft) × depth (in) ÷ 12
volume (cu yd)  = volume (cu ft) ÷ 27
volume (cu m)   = volume (cu ft) ÷ 35.3146667215
volume (liters) = volume (cu ft) × 28.316846592
bags            = ceil(volume (cu ft) ÷ bag size)

Dividing the depth by 12 converts inches to feet before multiplying by the area. One cubic yard contains 27 cubic feet, which is why bulk orders are quoted in cubic yards. Bag counts are rounded up to the next whole bag.

Assumptions and limitations

• The area is entered in square feet and the depth in inches.
• The bed is assumed to be a simple rectangle or a known area. For an irregular bed, divide it into simple shapes, calculate each area, and add them.
• The mulch layer is assumed to be spread at a uniform depth. Slopes, mounds, and uneven ground may require more material.
• The estimate does not account for settlement, compaction, or the amount of mulch that blows or washes away.
• The bag size varies by product. Check the label, especially for large compressed bags.
• The calculator does not include delivery fees, taxes, or the cost of edging and landscape fabric.

Frequently asked questions

How many bags of mulch are in a cubic yard?

A cubic yard is 27 cubic feet. At 2 cubic feet per bag, that is 13.5 bags, so you would need 14 bags to cover one cubic yard.

How deep should mulch be?

Two to four inches is typical for most garden beds. Less than two inches may not suppress weeds well, while more than four inches can prevent water and oxygen from reaching the soil.

Does mulch settle after installation?

Yes. Fresh organic mulch can settle as it decomposes, and rain can compact the surface. Ordering a little extra, or buying by the cubic yard for large beds, helps avoid a shortfall after settling.

Source

Reference: Calculator.net — Mulch Calculator.

This calculator provides an estimate. Check the bag label and your local supplier's coverage guidance before ordering.