Mulch Calculator for Flower Beds
Estimate mulch for annual and perennial flower beds at the right shallow depth.
Flower beds do best with a 2-inch layer of mulch — enough to hold moisture and block weeds without smothering shallow-rooted annuals and perennials. The calculator below starts at 2 inches; enter your bed size to see the cubic yards and bags you need.
Mulch Calculator
Estimate how much you need — and the cost.
- cubic feet 16.67
- cubic meters 0.472
- tons (US) 0.25
- tonnes 0.22
Tip: Keep mulch an inch or two away from plant stems and crowns so they do not stay damp and rot.
How it's calculated
1 cubic yard covers about 324 sq ft at 1 in deep / about 108 sq ft at 3 in deep; one 2 cu ft bag covers about 12 sq ft at 2 in deep.
See the full Mulch Calculator for the complete how-to, unit conversions, and data sources.
Mulch Calculator for Flower Beds FAQ
How deep should mulch be in flower beds?
About 2 inches. Deeper than that can suffocate shallow-rooted flowers and hold too much moisture against the stems.
How much mulch do I need for a flower bed?
Multiply the bed area by 2 inches and divide by 324 for cubic yards. A 100 sq ft bed at 2 inches needs about 0.6 cubic yards (around 8 bags).