Mulch, topsoil, and compost are sold by the cubic yard. Area times depth (in feet) divided by 27 gives the yards — the bedrock calc of every landscaping material order.
The example
500 sq ft bed, 3-inch depth.
| A | B | |
|---|---|---|
| 1 | Item | Value |
| 2 | 500 × 0.25 / 27 | — |
| 3 | Cubic yards | → ~4.6 |
The formula
The formula:
How it works
How it works:
- Convert depth to feet: inches ÷ 12.
- Multiply by area (sq ft) for cubic feet, then divide by 27 for cubic yards.
- ROUNDUP to whole or half yards since suppliers sell in increments.
- A cubic yard of mulch covers ~108 sq ft at 3 inches — a handy field check.
27 is the magic number. A cubic yard is 3×3×3 feet = 27 cubic feet, so every bulk-material calc ends in ÷ 27. Keep depth in feet (inches ÷ 12) and the formula is bulletproof for mulch, soil, or compost. Order a little extra and round up — running half a yard short means a second delivery fee that dwarfs the cost of the material.
Try it: interactive demo
Area (sq ft) and depth (inches).
Variations
Round up to order
Half-yard increments:
Bags instead of bulk
2-cu-ft bags:
Coverage per yard
Sq ft at a depth:
Pitfalls & errors
Depth in feet. Convert inches to feet (÷ 12) before multiplying.
Divide by 27. 27 cubic feet per cubic yard.
Round up. Order in the supplier’s increment, with a little extra.
Practice workbook
Frequently asked questions
How do I calculate mulch cubic yards in Excel?
How much does a cubic yard of mulch cover?
How many bags instead of bulk?
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