# Square Feet to Cubic Yards Calculator

> This square feet to cubic yards calculator needs one extra number, the depth, because area alone cannot be turned into volume. Enter both and read the yards to order.

**Quick answer:** You cannot convert square feet to cubic yards directly, because one is area and the other is volume. Add a depth: multiply square feet by depth in feet, then divide by 27. For 400 sq ft at 4 inches deep that is 133.3 cubic feet, or 4.94 cubic yards, and 5.43 yards with 10% extra.

_Last updated: October 8, 2026. Estimates only; confirm quantities with your supplier._

## How to convert square feet to cubic yards

Square feet measure area; cubic yards measure volume. There is no fixed conversion between them, because the result depends on how deep the material is. Once you pick a depth, the conversion is simple: convert the depth to feet, multiply by the area to get cubic feet, then divide by 27 (there are 27 cubic feet in a cubic yard).

      400 sq ft4 in400 × (4 ÷ 12) = 133.3 cu ft133.3 ÷ 27 = 4.94 cubic yardsVolume needs a third dimension: area × depth, then ÷ 27.**Field notes**
- Depth drives the answer: the same 400 sq ft needs 2.5 yd at 2 in and 7.4 yd at 6 in.
- Compacted base material (gravel, road base) settles; order 10–15% over the loose volume.

```
cubic feet = square feet × (depth in inches ÷ 12)
cubic yards = cubic feet ÷ 27
```

Example: 400 sq ft at 4 inches deep is 400 × 0.3333 = **133.3 cubic feet**, which is **4.94 cubic yards**. Add 10% for waste and settling and you order **5.43 cubic yards**, about 7.6 tons of gravel at 1.4 tons per yard.

### Coverage of one cubic yard at common depths

| Depth | Square feet covered by 1 cubic yard |
| --- | --- |
| 1 in | 324 sq ft |
| 2 in | 162 sq ft |
| 3 in | 108 sq ft |
| 4 in | 81 sq ft |
| 6 in | 54 sq ft |
| 8 in | 41 sq ft |
| 12 in | 27 sq ft |

The rule of thumb: **324 ÷ depth in inches** gives the square feet that one cubic yard covers. At 3 inches, one yard covers 108 sq ft; at 2 inches, 162 sq ft.

### Quantities for common areas at 4 inches deep

| Area | Cubic yards |
| --- | --- |
| 100 sq ft | 1.23 |
| 200 sq ft | 2.47 |
| 300 sq ft | 3.70 |
| 500 sq ft | 6.17 |
| 1000 sq ft | 12.35 |

### Common mistakes

- Dividing square feet by 27 directly. That skips the depth and gives a wrong answer.
- Mixing inches and feet. Convert the depth to feet before multiplying, or divide by 12.
- Forgetting waste. Uneven ground, settling and compaction mean you usually need 5–15% more.

For other shapes use the [cubic yard calculator](../cubic-yard-calculator/); to convert yards to weight, use the [yards to tons calculator](../yards-to-tons-calculator/); for a mulch bed see the [mulch calculator](../mulch-calculator/).

## Frequently asked questions

### How do I convert square feet to cubic yards?

Multiply the square feet by the depth in feet (inches ÷ 12) to get cubic feet, then divide by 27.

### How many square feet does a cubic yard cover?

Divide 324 by the depth in inches. At 3 inches one cubic yard covers 108 sq ft; at 4 inches, 81 sq ft.

### Why can't I convert square feet to cubic yards without a depth?

Square feet measure a flat area and cubic yards measure a volume. The depth is the missing dimension.

### How many cubic yards for 1,000 square feet?

At 4 inches deep, about 12.35 cubic yards. At 2 inches, about 6.17.

### Should I add extra for waste?

Usually yes: 5–15% covers settling, uneven ground and spills.

## Sources and further reading

- [NIST Special Publication 811: conversion factors](https://www.nist.gov/pml/special-publication-811/nist-guide-si-appendix-b-conversion-factors) — National Institute of Standards and Technology