Mulch Calculator

Calculate how much mulch you need for garden beds and landscaping.

Bed Shape

Length (feet)

Width (feet)

Depth (inches)

Custom Depth (inches)

Cost per Cubic Yard (optional, $)

Results

Area —

Volume —

2 cu ft bags —

3 cu ft bags —

Estimated Cost (bulk) —

Coverage is approximate. Actual amount varies with bed shape and existing mulch depth.

How to Calculate Mulch

Mulch is sold in cubic yards (bulk) or in bags (typically 2 or 3 cubic feet). To figure out how much you need, calculate the volume of your garden bed area.

Mulch Formula

Rectangle: Volume = Length × Width × Depth / 27
Circle: Volume = π × r² × Depth / 27
Ring: Volume = π × (outerR² - innerR²) × Depth / 27
Where length and width are in feet, depth in feet (divide inches by 12)

Recommended Mulch Depths

2 inches: Annual flower beds, thin topdressing over existing mulch
3 inches: Most garden beds and landscaping (standard recommendation)
4 inches: Weed suppression in new beds, around trees and shrubs
6 inches: Playground areas and pathways only (safety requirement for wood chips). Do not use 6" depth around plants as it can suffocate roots

Avoid piling mulch deeper than 4 inches around plants. It can suffocate roots and trap moisture against stems. Laying down landscape fabric before mulching helps prevent weeds and extends the life of your mulch bed.

Mulch Types & Coverage

All mulch types use the same volume calculation. Common options include:

Hardwood mulch: $30-45/cu yd. The most popular choice for landscaping
Pine bark: $30-40/cu yd. Lightweight, good for slopes
Cedar mulch: $35-50/cu yd. Natural insect resistance
Rubber mulch: $80-160/cu yd. Long-lasting for playgrounds
River rock: $100-200/ton. Permanent, no replacement needed

Bags vs. Bulk

For areas under 4-5 cubic yards, bags are convenient. Above that, bulk delivery is usually cheaper. One cubic yard of mulch is about 13.5 bags (2 cu ft each) or 9 bags (3 cu ft each). A good wheelbarrow is essential for moving bags or bulk mulch around your yard.