How many bags of mulch do I need for 400 square feet?

Landscape & Site WorkLandscape Bed Sizing

Bark & Wood Mulch Calculator

Calculate total bulk cubic yards and pre-packaged bags of bark mulch needed for garden beds, walkways, and tree rings.

Landscape & Site Work Field StandardsLandscape Bed Sizing

Engineering formulations calibrated to IPC, UPC & NEC specificationsSub-Zero Cold Climate Tolerances

Quick Summary & Key Answer

To calculate mulch: multiply square footage by depth in inches and divide by 324 to get cubic yards. A 400 sq ft garden bed mulched to a standard 3-inch depth requires 3.7 cubic yards of bulk mulch, or fifty (50) standard 2-cubic-foot bags.

1 Cubic Yard of mulch covers 108 sq ft at 3 inches deep (or 162 sq ft at 2 inches).
There are 13.5 two-cubic-foot bags in 1 cubic yard.
Never pile mulch against tree trunks (mulch volcanos cause fatal fungal bark rot).

Interactive Calculator

Adjust inputs for real-time results

Garden Bed Lengthfeet

feet

Garden Bed Widthfeet

feet

Mulch Depth

Calculated OutputMulch Sized

Bulk Mulch Required

3.70 Yds³cubic yards

2.0 Cu Ft Pre-Packaged Bags: 50 bags
3.0 Cu Ft Large Bags: 34 bags
Total Bed Surface Area: 400 sq ft
Total Volume in Cubic Feet: 100 cu ft

Note: Maintain a 3-inch gap around tree trunks ('donut, not a volcano') to prevent bark rot and rodent damage.

Recommended Mulch Depth

A 3-inch layer blocks 90% of weed germination while conserving soil moisture; deeper layers can suffocate shallow feeder roots.

Frequently Asked Questions

Common questions regarding this calculation and code compliance

At a standard 3-inch depth, 400 square feet requires fifty (50) two-cubic-foot bags (or 3.7 cubic yards).