Mulch Calculator
By Taro Schenker | Updated February 11, 2026
Quick Answer: To calculate mulch, multiply Length (ft) × Width (ft) × Depth (in) ÷ 12 ÷ 27 to get cubic yards. One cubic yard covers 108 sq ft at 3 inches deep. Standard mulch bags are 2 cubic feet. Typical densities: wood chip 450 lbs/cu yd, bark 550, shredded hardwood 600, rubber 1,200. Add 10% for waste and settling. For a 10 × 10 ft bed at 3 inches deep, you need 0.93 cubic yards (about 14 bags).
Calculate how much mulch you need for your garden beds, landscaping, or pathways. Enter your dimensions and mulch depth to get the exact amount in cubic yards, number of bags, total weight, and estimated cost.
How to Calculate Mulch
The formula for calculating mulch volume is straightforward:
- Measure the length and width of your area in feet.
- Decide on your mulch depth (2-4 inches for most applications).
- Multiply length × width to get the area in square feet.
- Multiply the area by the depth (converted to feet) to get the volume in cubic feet.
- Divide by 27 to convert to cubic yards (the standard bulk purchasing unit).
- Add 10% for waste and settling.
Mulch Coverage Chart
Quick reference for how much area one cubic yard of mulch covers at different depths:
| Depth | Coverage per Cubic Yard | Bags per 100 sq ft |
|---|---|---|
| 1 inch | 324 sq ft | 5 bags |
| 2 inches | 162 sq ft | 9 bags |
| 3 inches | 108 sq ft | 14 bags |
| 4 inches | 81 sq ft | 17 bags |
Tips for Buying Mulch
- Bulk vs bags: For projects needing more than 3 cubic yards, bulk delivery is typically 50% cheaper per yard.
- Timing: Mulch prices are lowest in late winter and early spring before the landscaping season peaks.
- Delivery: Most landscape supply companies deliver bulk mulch for $50-100 depending on distance and quantity.
- Settling: Fresh mulch will settle 10-20% over the first few weeks. Order slightly more than you calculate.
- Depth matters: Too little mulch (<2 inches) won't suppress weeds effectively. Too much (>4 inches) can suffocate plant roots and trap moisture.
Formula Summary
Mulch Volume Formula: To calculate the cubic yardage of mulch needed, multiply the Length (ft) × Width (ft) × Depth (in), divide by 12 to convert depth to feet, then divide by 27 to convert cubic feet to cubic yards.
$$V_{\text{cu yd}} = \frac{L_{\text{ft}} \times W_{\text{ft}} \times D_{\text{in}}}{12 \times 27}$$
Bags Formula: $$\text{Bags} = \lceil \frac{V_{\text{cu ft}}}{2} \rceil$$ (standard bag = 2 cu ft)
Weight Formula: $$W_{\text{lbs}} = V_{\text{cu yd}} \times \rho$$ where $\rho$ is the mulch density in lbs/cu yd.
| Mulch Type | Density (lbs/cu yd) |
|---|---|
| Wood Chip | 450 |
| Bark | 550 |
| Shredded Hardwood | 600 |
| Rubber | 1,200 |
| Dyed | 500 |
Standard Assumptions: Waste factor of 10% accounts for settling, uneven terrain, and irregular bed shapes. Standard bag size is 2 cubic feet. 1 cubic yard = 27 cubic feet.
Related Calculators
- Gravel Calculator — calculate gravel for driveways, paths, and fill
- Sand Calculator — estimate sand for leveling, sandboxes, and masonry
- Cubic Yard Calculator — convert any dimensions to cubic yards
Estimates are for planning purposes only. Consult a qualified contractor for critical projects. Actual material requirements may vary based on site conditions, waste, and installation methods.
Pricing last verified: February 2026. Material prices vary by region, season, and supplier. Prices shown are national averages for planning purposes.