Mulch Calculator
Enter your garden bed dimensions and desired depth to instantly calculate how many cubic yards or bags of mulch you need — with an estimated cost.
Mulch coverage by depth
| Depth | Per 100 sq ft | 2 cu ft bags | Best For |
|---|---|---|---|
| 1 in (2.5 cm) | 0.31 yd³ | 5 bags | Thin refresh over existing mulch |
| 2 in (5 cm) | 0.62 yd³ | 10 bags | Maintenance layer, annual refresh |
| 3 in (7.5 cm) | 0.93 yd³ | 15 bags | New beds, weed suppression (recommended) |
| 4 in (10 cm) | 1.23 yd³ | 20 bags | Maximum weed control, moisture retention |
| 6 in (15 cm) | 1.85 yd³ | 31 bags | Paths, playgrounds (may limit plant growth) |
Mulch cost by type
| Type | Bulk (per yd³) | Bags (2 cu ft) | Notes |
|---|---|---|---|
| Shredded Wood | $25–$40 | $3–$5 | Most common; decomposes slowly |
| Cedar / Cypress | $35–$55 | $5–$8 | Natural pest repellent; lasts longer |
| Rubber Mulch | $60–$120 | $8–$15 | Playgrounds; lasts 10+ years |
| Pine Straw | $20–$35 | $3–$5 | Acid-loving plants; lightweight |
| Cocoa Hull | $40–$70 | $6–$10 | Dark color; chocolate scent; toxic to dogs |
| Compost | $30–$60 | $4–$8 | Improves soil while suppressing weeds |
Rubber mulch calculator — playground coverage
Rubber mulch is the standard for playgrounds and swing sets. ASTM F1292 requires at least 6 inches of loose fill for fall protection from equipment up to 7 ft high. Use the calculator above with Rubber Mulch selected, or reference this table:
| Area | At 6 in deep | At 9 in deep | Approx. bags (1.5 cu ft) |
|---|---|---|---|
| 8×8 ft (64 sq ft) | 1.19 yd³ | 1.78 yd³ | 11–17 bags |
| 10×10 ft (100 sq ft) | 1.85 yd³ | 2.78 yd³ | 17–25 bags |
| 12×12 ft (144 sq ft) | 2.67 yd³ | 4.00 yd³ | 24–36 bags |
| 15×15 ft (225 sq ft) | 4.17 yd³ | 6.25 yd³ | 38–56 bags |
| 20×20 ft (400 sq ft) | 7.41 yd³ | 11.1 yd³ | 67–100 bags |
Add 15% loose factor — rubber mulch compresses under foot traffic. For a 10×10 ft swing set zone at 6 inches, order ~6.4 yd³ not 5.56 yd³.
Mulch loose factor & how to measure existing depth
Loose factor: Bagged and bulk mulch settles 10–20% after delivery and watering. Always order 10–15% more than the calculator result for new installations.
Measuring existing depth: Push a ruler or pencil straight down through the existing mulch layer in several spots. Average the readings. If you have 1.5 inches already and want 3 inches total, only add 1.5 inches (not 3).
Bags vs bulk: 1 cubic yard = 13.5 bags (2 cu ft each) or 9 bags (3 cu ft each). Bulk delivery breaks even at roughly 2–3 cubic yards depending on delivery fees in your area.