Square Feet to Cubic Yards Calculator

What is a square feet to cubic yards calculator?

A square feet to cubic yards calculator turns a flat surface measurement into the amount of material needed to fill it to a given depth. You enter the area you are covering in square feet and how deep you want the layer in inches, and the calculator returns the resulting volume in both cubic yards and cubic feet.

This is one of the most common calculations in construction and landscaping. Concrete, mulch, gravel, topsoil, and sand are almost always sold and delivered by the cubic yard, but jobs are measured on site by their footprint in square feet and the desired thickness in inches. Bridging those two units is exactly what this tool does.

How does it work?

Square feet measure area (two dimensions) while cubic yards measure volume (three dimensions). To go from one to the other you need a third dimension — the depth of the layer. Because area is expressed in feet but depth is given in inches, the depth is first converted to feet by dividing by 12.

Multiplying area by depth (both in feet) gives the volume in cubic feet:

$ft^3 = ft^2 \times \frac{d}{12}$

Here $d$ is the depth in inches, so $d/12$ is the depth in feet. Since one cubic yard equals 27 cubic feet (a yard is 3 feet, and $3 \times 3 \times 3 = 27$), dividing by 27 converts the volume to cubic yards:

$yd^3 = \frac{ft^2 \times (d/12)}{27}$

Worked examples

Example 1 — a 100 ft² slab, 6 inches deep. The depth in feet is $6/12 = 0.5$ ft, so the volume in cubic feet is $100 \times 0.5 = 50$ ft³. Dividing by 27 gives:

$yd^3 = \frac{50}{27} \approx 1.8519 \text{ yd}^3$

You would order roughly 1.85 cubic yards of material (and likely round up to allow for waste and over-excavation).

Example 2 — a 324 ft² area, 4 inches deep. The depth in feet is $4/12 \approx 0.3333$ ft, so the volume in cubic feet is $324 \times (4/12) = 108$ ft³. Dividing by 27 gives a clean result:

$yd^3 = \frac{108}{27} = 4 \text{ yd}^3$

Exactly 4 cubic yards.

Practical notes

• A handy shortcut: a 1-inch-deep layer over an area in square feet equals that area divided by 324 in cubic yards, because $27 \times 12 = 324$. So 324 ft² at 1 inch is exactly 1 cubic yard.
• Always order a little extra. Suppliers and contractors typically add 5–10% to the calculated volume to cover spillage, compaction, and uneven sub-grade.
• If you already know the volume in cubic feet, you can skip the area-and-depth step and convert directly with the cubic feet to cubic yards converter.
• To estimate the cost or coverage of a single cubic yard, see the cubic yard calculator, and to measure an irregular footprint first, use the square footage calculator.

FAQ

How many square feet does a cubic yard cover?

It depends on depth. A cubic yard is 27 cubic feet, so spread 1 inch deep it covers about 324 ft²; at 2 inches it covers about 162 ft²; and at 6 inches it covers about 54 ft². Deeper layers cover proportionally less area.

Why is the depth divided by 12?

The area is in square feet, so every dimension in the volume formula must also be in feet. Since depth is entered in inches and there are 12 inches in a foot, dividing the inches by 12 converts the depth to feet before it is multiplied by the area.