How to calculate mulch
- Choose US or metric units. Mulch is preselected.
- Enter the length and width of each bed, or choose Circle for round beds and tree rings.
- Set the depth: 5–8 cm (2–3 in) is typical. 7.5 cm (3 in) is filled in.
- Read the volume and the number of bags; for large areas, order bulk mulch by the cubic yard or m³.
How deep should mulch be?
A layer of 5–8 cm (2–3 in) suppresses weeds, keeps moisture in the soil and evens out temperature. Thinner layers let weeds through; deeper ones can starve roots of oxygen and keep stems too wet. Keep mulch a few centimetres away from plant stems and tree trunks to avoid rot; "mulch volcanoes" piled against trees do real harm. Top up existing mulch by just 2–5 cm each year.
One cubic yard covers about 108 sq ft at 3 in deep, or 162 sq ft at 2 in. A 2 cu ft bag covers 8 sq ft at 3 in. Bulk mulch is usually much cheaper than bags for beds over about 100 sq ft (10 m²). The calculator runs in your browser.
FAQ
How many bags of mulch in a yard?
About 13.5 bags of 2 cu ft, or 9 bags of 3 cu ft.
How much area does a 2 cu ft bag cover?
About 12 sq ft at 2 in deep or 8 sq ft at 3 in.
Should I remove old mulch?
Usually not; just rake it and add a thinner fresh layer.