Mulch Calculator
Calculate how much mulch you need in cubic yards and bags. Enter your bed area and mulch depth to get the exact quantity to order.
Last updated 2026-08-21
What Is a Mulch Calculator?
The mulch calculator figures out how much mulch you need to cover a garden bed or landscaped area. It turns your bed area and target depth into cubic yards for bulk delivery or the number of 2 cu ft bags for a quick trip to the garden center.
How It Works
Volume = Area × (Depth ÷ 12). Cubic yards = Volume ÷ 27. Bags = ceil(Volume ÷ 2) for 2 cu ft bags.
Example
For 100 sq ft at 3 in deep: 100 × 0.25 = 25 cu ft ≈ 0.93 cu yd → 13 × 2 cu ft bags.
How to Calculate
- Measure the length and width of each bed in feet and multiply to get the area. For a 20 ft by 5 ft border bed, that is 100 sq ft.
- Choose your mulch depth. A 3 in layer is a good default for weed control and moisture retention.
- Enter the area and depth. The tool converts to cubic feet, then to cubic yards: 100 sq ft at 3 in deep is 25 cu ft, about 0.93 cubic yards.
- Read the bag count. With 2 cu ft bags, 25 cu ft rounds up to 13 bags, the minimum you should buy.
- Order 5 to 10% extra to cover settling and uneven beds, then apply the mulch evenly.
Mulch Coverage by Depth (One Cubic Yard)
| Mulch Depth | Coverage in Square Feet | 2 cu ft Bags per 100 sq ft |
|---|---|---|
| 2 in | 162 sq ft | 9 bags |
| 3 in | 108 sq ft | 13 bags |
| 4 in | 81 sq ft | 17 bags |
| 5 in | 65 sq ft | 21 bags |
| 6 in | 54 sq ft | 25 bags |
Sources
Frequently Asked Questions
How deep should mulch be?
2–3 in is typical for beds. Too deep can smother plants; too shallow lets weeds through.
Bulk or bagged mulch?
Bulk is cheaper for large areas; bags (usually 2 cu ft) are easier for small beds.
How much does a yard of mulch cover?
One cubic yard covers about 108 sq ft at 3 in deep.
Estimate the cost with the Landscaping Cost Calculator. Also try: Gravel Calculator, Topsoil Calculator or browse Landscaping Calculators