Mulch Calculator
Calculate exactly how much mulch to buy for any garden bed or landscape area. Enter dimensions and desired depth to get cubic yards, cubic feet, bags needed, and estimated cost for bagged or bulk mulch.
Mulch Calculator Tool
Why use this free mulch calculator?
Built with the features most competitors miss — deeper inputs, benchmark data, and actionable guidance alongside the core calculation.
How to use this mulch calculator
Coverage per cubic yard by depth
| Depth | Per cu yd | Per 2 cu ft bag | Typical use |
|---|---|---|---|
| 1 inch | 324 sq ft | 21.6 sq ft | Light top-dress |
| 2 inches | 162 sq ft | 10.8 sq ft | Standard application |
| 3 inches | 108 sq ft | 7.2 sq ft | New beds / heavy mulch |
| 4 inches | 81 sq ft | 5.4 sq ft | Deep mulch / weed suppression |
How this calculator compares
LazyTools fills the gaps most competing tools leave open — deeper analysis, benchmark context, and actionable guidance alongside the core calculation.
| Feature | LazyTools | OmniCalculator | Lowes.com | HomeDepot.com |
|---|---|---|---|---|
| Cubic yards and cubic feet | ✓ Yes | ✓ | ✓ | ✓ |
| Bags needed | ✓ Yes | ✓ | ✓ | ✓ |
| Cost estimate | ✓ Yes | ✓ | ✓ | ✓ |
| Custom depth | ✓ Yes | ✓ | ✗ | ✗ |
| Coverage reference table | ✓ Yes | ✗ | ✗ | ✗ |
| No sign-in required | ✓ Yes | ✓ | ✗ | ✗ |
Mulch Calculator: Complete Guide
Mulch is one of the most cost-effective investments in the garden, suppressing weeds, retaining moisture, moderating soil temperature, and adding organic matter as it breaks down. Calculating the right quantity saves money and prevents the frustration of running short mid-project.
The mulch calculation formula
Volume (cu yd) = Area (sq ft) x Depth (in) / 324. At 3-inch depth (the recommended minimum for weed suppression), one cubic yard covers 108 sq ft. At 2 inches, it covers 162 sq ft. Add 10% for settling and uneven application.
Recommended mulch depths by purpose
Moisture retention: 2 to 3 inches. Weed suppression: 3 to 4 inches (weed seeds need light; deeper layers block more effectively). Around trees: 3 to 4 inches in a ring, kept 6 inches clear of the trunk. Playgrounds and pathways: 3 to 6 inches for impact attenuation and drainage. Vegetable gardens: 2 to 3 inches of straw, wood chips, or shredded leaves.
Types of mulch and their properties
Shredded hardwood or bark: most common, slow to decompose, good for shrub beds. Pine bark: acidic when fresh, good for acid-loving plants. Cedar or cypress: naturally insect-repellent, slow to decompose, retains colour well. Straw: excellent for vegetable gardens, decomposes and adds organic matter. Wood chips: best from arborists (free through Chip Drop), excellent long-term organic matter. Stone/gravel: permanent, no organic matter benefit, reflects heat.
Bulk vs bagged mulch
Bagged mulch (2 cu ft bags at $5 to $12 each) is convenient for small projects. Bulk mulch from a landscape supplier ($25 to $60/cu yd delivered) is dramatically cheaper for large areas. The crossover point is around 3 to 5 cubic yards where delivery costs are offset. A 2 cu ft bag = 0.074 cu yd; so bagged mulch at $8/bag = $108/cu yd equivalent — 2 to 4x the bulk price.
Mulch ring around trees: the right way
Extend mulch to the drip line (outer edge of canopy) if possible, minimum 3 feet from the trunk. Depth: 2 to 4 inches. Never pile mulch against the trunk ("mulch volcano") as this promotes bark rot, pest harbourage, and girdling roots. A properly mulched tree ring reduces competition from turf, retains moisture, and dramatically reduces mower and trimmer damage to the trunk.