Mulch Calculator

How to use this calculator

1. Enter or choose units.
2. Enter or choose bed length.
3. Enter or choose bed width.
4. Enter or choose depth.
5. Enter or choose bag size.
6. The mulch needed updates as you type. Use Copy result or Share to keep it.

Method

Volume = Length × Width × Depth; Bags = Volume ÷ Bag size, rounded up; 1 yd³ = 27 ft³ = 0.7646 m³

Depth

thickness of the mulch layer (converted from cm or inches)

Bag size

volume printed on the bag

Worked example

1. Area = 5 × 4 = 20 m². Depth 7.5 cm = 0.075 m.
2. Volume = 20 × 0.075 = 1.5 m³ = 1,500 litres.
3. 1,500 ÷ 50 L per bag = 30 bags.

A 5 × 4 m bed mulched 7.5 cm deep needs 1.5 m³ (about 1.96 yd³), or 30 bags of 50 litres.

What the result means

For larger beds, bulk delivery by the cubic metre or yard is usually cheaper than bags. Fresh mulch settles, so some gardeners add a little extra.

Assumptions and limits

• A rectangular bed of even depth. For irregular beds, measure the area another way and use length = area and width = 1.
• Mulch compacts and settles over time; the volume is for the loose material at the depth entered.