Mulch Calculator
Estimate how much mulch you need for beds and gardens — in cubic yards, cubic meters, and the number of standard 2 cu ft bags — from your area and depth.
Result
| Volume | |
| Bags (2 ft³ each) |
Units & conversions used
Imperial inputs are square feet (area) and inches (depth); results are shown in cubic feet, cubic yards (1 yd³ = 27 ft³), cubic meters (1 ft³ = 0.02832 m³) and 2 ft³ bags. Metric inputs are converted first: 1 m² = 10.7639 ft², 1 cm = 0.3937 in.
Formula & source
V(yd³) = V(ft³) ÷ 27
bags = V(ft³) ÷ 2 (rounded up)
Source: basic geometry — volume of a flat layer, no external authority needed. A widely used garden-industry rule of thumb says one cubic yard covers about 108 ft² at 3 inches deep; you can check it against the formula (108 × 3 ÷ 12 = 27 ft³ = 1 yd³). Bag count assumes the standard US 2 cu ft bag and rounds up, since partial bags cannot be bought.
Worked example (you can verify by hand)
Input: 200 ft² area × 3 in deep.
- Volume: 200 × 3 ÷ 12 = 50 ft³
- Cubic yards: 50 ÷ 27 = 1.8519 yd³
- Bags: 50 ÷ 2 = 25 bags (2 ft³ each)
Expected output: 50 ft³ = 1.85 yd³ (1.42 m³), 25 bags.
Limitations — what this cannot do
- Estimates volume only: it does not choose the mulch type (bark, wood chips, pine straw, rubber) — different materials and particle sizes settle differently.
- Mulch settles after spreading: fresh material can compress 10–25% over the first season, so a bed may need topping up.
- Assumes a level bed of uniform depth. Irregular beds should be measured in sections, and oddly shaped corners may need rounding up.
FAQ
How many bags of mulch do I need for a 200 sq ft bed at 3 inches deep?
200 × (3 ÷ 12) = 50 ft³. At 2 ft³ per bag that is exactly 25 bags. In bulk terms that is 50 ÷ 27 = 1.85 yd³ — ordering bulk is usually cheaper at that size.
How much area does one cubic yard of mulch cover?
One cubic yard (27 ft³) covers about 108 ft² at 3 inches deep, about 81 ft² at 4 inches, and about 162 ft² at 2 inches. Check: 108 × (3 ÷ 12) = 27 ft³.
How deep should mulch be?
2–4 inches is the common recommendation for weed control and moisture retention around established plantings. Keep mulch a few inches away from stems and trunks to avoid rot.
Bags or bulk — which should I buy?
Bags are convenient for small jobs; a 2 ft³ bag covers about 8 ft² at 3 inches. For roughly a cubic yard or more (around 14+ bags), bulk delivery is usually cheaper per yard.
How much mulch do I need?
Use the calculator at the top of this page, or the common industry formula: area (ft²) × depth (in) ÷ 324 = cubic yards. (Why 324: area × depth ÷ 12 gives cubic feet, and dividing by 27 converts to cubic yards, so 12 × 27 = 324.) For example, a 200 ft² bed at 3 inches deep needs 200 × 3 ÷ 324 = 1.85 yd³. This formula is widely published by mulch suppliers and landscapers; it gives the same result as the calculator above.