Mulch Calculator
Free, with no sign up. Calculations run on your device; your entries stay in this browser.
Material quantity
Area: rectangle = length × width; circle = π × (diameter / 2)²; or enter total area. ft³ = area in ft² × depth in inches / 12; yd³ = ft³ / 27; m³ = ft³ × 0.3048³. Bags = round up(ft³ / 2) or round up(ft³ / 3).
Primary source: NIST SP 811 volume conversions; area × depth gives the volume of a uniform layer.
Worked example
A 10 ft × 8 ft bed at 3 inches deep needs 80 × 3 / 12 = 20 ft³ = 0.740741 yd³ ≈ 0.566337 m³. Choose 10 bags of 2 cu ft each, or 7 bags of 3 cu ft each; the latter supplies 21 ft³.
Use a common depth for the whole measured area. Circle input is diameter across the bed, not radius. Changing units reinterprets the values: enter dimensions in the selected unit, and always enter depth in inches. No allowance for settling, compaction or waste is added.
How to use this tool
Choose rectangle, circle or total area. Enter dimensions in feet or metres and depth in inches, then Calculate the mulch quantity.
Frequently asked questions
How are mulch bags rounded?
Divide the required cubic feet by the volume on the bag and round up to a whole bag. Choose either the 2 cu ft count or the 3 cu ft count.
Can I enter several garden beds?
Choose total area and enter the sum of all bed areas in square feet or square metres, with one common depth in inches.
Does this recommend mulch depth?
No. Enter the depth you plan to use. The calculation measures a uniform layer and does not account for settling, uneven ground or extra material.