How is mulch volume calculated?

Volume = Length × Width × Depth for rectangular areas, or π × (Diameter / 2)² × Depth for circular areas. Convert depth to the same unit as the length and width before multiplying. Divide cubic feet by 27 to get cubic yards.

How many cubic yards of mulch do I need?

Divide the total volume in cubic feet by 27 to get cubic yards. For example, a 10 ft × 20 ft bed at 3 inches deep = 10 × 20 × (3/12) = 50 ft³ ÷ 27 ≈ 1.85 cubic yards.

How many bags of mulch equal a cubic yard?

A 2 cu ft bag: 13.5 bags per cubic yard. A 3 cu ft bag: 9 bags per cubic yard. A 2.8 cu ft bag: about 9.6 bags per cubic yard.

How deep should I apply mulch?

For weed suppression and moisture retention, 2–4 inches (5–10 cm) is recommended. Avoid applying more than 4 inches, as very thick mulch can suffocate plant roots and promote rot.

Why should I add a waste factor?

Mulch settles over time and some is lost when spreading around edges or irregular shapes. Adding 5–10% to your calculated amount ensures you will not run short.

Is bulk or bagged mulch more economical?

Bulk mulch is typically less expensive per cubic yard for larger projects (over 2–3 yards). Bagged mulch is convenient for small areas and easy to transport in a standard vehicle.

How much area does a 2 cubic foot bag of mulch cover?

About 12 sq ft at 2 inches deep, 8 sq ft at 3 inches or 6 sq ft at 4 inches. A 3 cu ft bag covers 18, 12 or 9 sq ft at the same depths.

Should mulch touch tree trunks?

No. Keep mulch a few inches away from trunks and plant stems. Piling it against the bark (volcano mulching) holds moisture there and invites rot and pests.

Mulch Calculator

Calculate how many cubic yards or bags of mulch you need to cover any area at a given depth.

Cubic yards of mulch = length (ft) × width (ft) × depth (in) ÷ 324.

Area & Depth

Length (ft)

Width (ft)

Depth (in)

Waste Factor (%)

Bag Size (for bagged mulch)

Quick answer

Cubic yards of mulch = length (ft) × width (ft) × depth (in) ÷ 324. One cubic yard covers 162 sq ft at 2 inches, 108 sq ft at 3 inches or 81 sq ft at 4 inches. A 10 × 20 ft bed at 3 inches needs about 1.85 cubic yards, or 25 bags of 2 cu ft, before the waste allowance.

Examples

Depth	1 cubic yard covers	Per 100 sq ft
2 in	162 sq ft	0.62 yd³ (9 bags of 2 cu ft)
3 in	108 sq ft	0.93 yd³ (13 bags of 2 cu ft)
4 in	81 sq ft	1.23 yd³ (17 bags of 2 cu ft)

Enter your bed size and depth.

Summary

A free online mulch calculator that estimates the volume of mulch (cubic yards and cubic feet) and the equivalent number of bags needed for any rectangular or circular area. Enter your area dimensions and desired mulch depth, add a waste factor, and get instant results in both bulk and bagged quantities. Supports Imperial and Metric units.

How it works

Select your area shape: rectangular or circular.
Choose Imperial (feet / inches) or Metric (meters / centimeters) units.
Enter the length and width (or diameter for circular areas).
Enter the desired mulch depth.
Select the bag size if you plan to buy bagged mulch.
Click Calculate to see cubic yards, cubic feet, and the number of bags needed.
Add a waste percentage (5–10% recommended) to account for settling and uneven spreading.

Use cases

Estimating mulch volume for garden beds and flower borders.
Calculating how many bags of mulch to buy for a landscaping project.
Planning bulk mulch orders for large yards or commercial properties.
Determining mulch quantity for tree rings or playgrounds.
Budgeting mulch for vegetable garden walkways.
Comparing cost of bulk cubic yards vs. bagged mulch.

Frequently Asked Questions

Last updated: 2026-05-25 · Reviewed by Nham Vu