Mulch Calculator

Measure your beds, choose a depth and get the exact amount of mulch in cubic yards, cubic feet, cubic metres and bags, including how far a single yard will spread.

View formula

Cubic feet = area (sq ft) × depth (in) ÷ 12 Cubic yards = cubic feet ÷ 27 Coverage of 1 cu yd = 324 ÷ depth (in) sq ft Metric: m³ = area (m²) × depth (cm) ÷ 100

How to use the Mulch Calculator

Choose rectangle or circle (for tree rings).
Enter the bed size and the mulch depth, 2 to 3 inches suits most beds.
If you have several beds of the same size, enter how many.
Choose a bag size and press Calculate.

Mulch formula

Cubic yards = (area in sq ft × depth in inches ÷ 12) ÷ 27

A handy shortcut: one cubic yard of mulch covers 324 sq ft at 1 inch deep. Divide 324 by your depth in inches to see how far a yard goes, 162 sq ft at 2 in, 108 sq ft at 3 in.

Worked example

Mulching 200 sq ft of shrub borders at 3 inches with 2 cu ft bags:

Volume: 200 × 3 ÷ 12 = 50 cu ft
Cubic yards: 50 ÷ 27 = 1.85 cu yd
Bags: 50 ÷ 2 = 25 bags

Recommended mulch depth

Mulch type	Depth	Best for
Fine shredded bark	2 to 3 in	Flower beds, perennials
Wood chips / nuggets	3 to 4 in	Shrub borders, paths, tree rings
Straw	3 to 6 in (settles fast)	Vegetable gardens
Compost as mulch	1 to 2 in	Vegetables, annual beds
Gravel / stone	2 to 3 in	Xeriscapes, drainage areas

Tips for mulching

Keep mulch a few inches away from stems and tree trunks, mulch piled against bark (a “mulch volcano”) traps moisture and invites rot and pests.
Weed and water the bed before mulching so the mulch locks moisture in.
If you are topping up an existing layer, measure only the depth you are adding.

FAQ