How to Calculate Mulch
Measure your bed's length and width in feet, choose your depth, then use the formula: Cubic Yards = Area (sq ft) × Depth (inches) ÷ 324. This calculator does the math and converts to bags or bulk yards.
Recommended Depths
- 2 inches: Light refresh of existing beds
- 3 inches: Standard coverage for most beds (most common)
- 4 inches: New beds or heavy weed suppression
- 6 inches: Pathways with heavy foot traffic
Never apply mulch deeper than 4 inches around plants. Excessive depth suffocates roots and traps moisture, causing rot.
Coverage Chart (per cubic yard)
- 2" deep: 162 sq ft
- 3" deep: 108 sq ft
- 4" deep: 81 sq ft
A standard 2 cu ft bag covers about 8 sq ft at 3 inches deep. One cubic yard equals roughly 13.5 bags.
Bulk vs Bagged Mulch
- Bagged ($3-6 per bag): Convenient for small beds under 200 sq ft, easy to transport and store
- Bulk ($25-45 per cubic yard): 30-50% cheaper for large projects, delivered by truck
For areas over 200-300 sq ft, bulk is almost always more economical. A cubic yard of mulch weighs 400-800 lbs depending on moisture content.
Choosing the Right Material
- Shredded bark: Best all-around. Affordable, stays in place, decomposes to enrich soil
- Wood chips: Longer lasting than bark. Better for pathways than garden beds
- Pine straw: Naturally acidic — great for azaleas, blueberries, and rhododendrons
- Rubber mulch: Permanent, doesn't decompose. Best for playgrounds, not gardens
- Pea gravel: Decorative with excellent drainage. Won't decompose or attract pests
- River rock: Permanent solution, no annual replacement. Retains heat in summer
Application Tips
- Keep mulch 3-6 inches away from tree trunks and plant stems — build a donut shape, not a volcano
- Organic mulch needs refreshing every 1-2 years as it decomposes
- Best time to buy: mid-spring to early summer when stores run promotions (up to 40% off)
- Lay landscape fabric underneath for extra weed suppression, especially with rock or gravel
- Top up annually when depth drops below 2 inches