Square Feet to Cubic Yards
By Emiliano · Last updated 2026-11-13
Square feet is an area; cubic yards is a volume. To convert one to the other, you need a third dimension — depth or thickness. Once you have that, the formula is square feet × depth in inches ÷ 324 = cubic yards. The table below handles the most common depths; the calculator at the top does the arithmetic for you.
Why 324? One cubic yard is 27 cubic feet (3 × 3 × 3). One foot is 12 inches. So 27 × 12 = 324. Dividing square feet times inches by 324 gives you cubic yards directly.
Square Feet to Cubic Yards Calculator
The Formula
The conversion from square feet to cubic yards is a two-step calculation that combines area, depth, and volume:
Cubic yards = (Square feet × Depth in inches) ÷ 324
If you want to do it in cubic feet first (because that's how most people think about volume), the formula is:
Cubic feet = Square feet × (Depth in inches ÷ 12)
Cubic yards = Cubic feet ÷ 27
The two formulas produce the same answer. The 324 shortcut just combines them into one step.
Conversion Chart by Depth
Common square footages converted to cubic yards at the depths used most in construction and landscaping:
| Square Feet | 1" deep | 2" deep | 3" deep | 4" deep | 6" deep | 12" deep |
|---|---|---|---|---|---|---|
| 50 sq ft | 0.15 | 0.31 | 0.46 | 0.62 | 0.93 | 1.85 |
| 100 sq ft | 0.31 | 0.62 | 0.93 | 1.23 | 1.85 | 3.70 |
| 200 sq ft | 0.62 | 1.23 | 1.85 | 2.47 | 3.70 | 7.41 |
| 300 sq ft | 0.93 | 1.85 | 2.78 | 3.70 | 5.56 | 11.11 |
| 400 sq ft | 1.23 | 2.47 | 3.70 | 4.94 | 7.41 | 14.81 |
| 500 sq ft | 1.54 | 3.09 | 4.63 | 6.17 | 9.26 | 18.52 |
| 750 sq ft | 2.31 | 4.63 | 6.94 | 9.26 | 13.89 | 27.78 |
| 1,000 sq ft | 3.09 | 6.17 | 9.26 | 12.35 | 18.52 | 37.04 |
| 1,500 sq ft | 4.63 | 9.26 | 13.89 | 18.52 | 27.78 | 55.56 |
| 2,000 sq ft | 6.17 | 12.35 | 18.52 | 24.69 | 37.04 | 74.07 |
All values rounded to two decimal places. For depths not shown, use the formula: cubic yards = (sq ft × inches) ÷ 324.
Common Uses and Typical Depths
Different materials call for different depths. Here are the standard depth ranges by application:
| Application | Typical Depth | Material Calculator |
|---|---|---|
| Concrete slab (residential) | 4 inches | Concrete Slab Calculator |
| Concrete driveway | 5–6 inches | Concrete Slab Calculator |
| Gravel driveway base | 4–6 inches | Gravel Calculator |
| Mulch bed | 2–3 inches | Mulch Calculator |
| Topsoil for new lawn | 4–6 inches | Topsoil Calculator |
| Sand bedding for pavers | 1 inch | Paver Calculator |
| Road base aggregate | 6–8 inches | Gravel Calculator |
Skip the manual math
Concrete Slab Calculator → · Gravel Calculator → · Mulch Calculator →
Worked Examples
Three real-world examples showing how this conversion is used in practice:
Example 1: Concrete slab for a shed
A 12 × 16 foot shed base is 192 square feet. At 4 inches thick, cubic yards = (192 × 4) ÷ 324 = 2.37 cubic yards. Add 5–10% for waste and you order 2.5 to 2.6 cubic yards of ready-mix concrete.
Example 2: Gravel driveway
A 20 × 40 foot driveway is 800 square feet. At 6 inches deep, cubic yards = (800 × 6) ÷ 324 = 14.81 cubic yards. Gravel is sold by the cubic yard or by the ton, so you'd order 15 cubic yards or about 21 tons (at 1.4 tons per cubic yard).
Example 3: Mulch for a garden bed
A 300 square foot bed at 3 inches deep needs (300 × 3) ÷ 324 = 2.78 cubic yards. Bagged mulch is sold in 2 cubic foot bags; 2.78 cubic yards = 75 cubic feet = about 38 bags.
Frequently Asked Questions
How do I convert square feet to cubic yards?
Multiply square footage by depth in inches, then divide by 324. Formula: cubic yards = (square feet × depth in inches) ÷ 324. The 324 comes from 27 cubic feet per cubic yard times 12 inches per foot. You need the depth — square feet alone cannot become cubic yards without a third dimension.
How many cubic yards is 1,000 square feet?
It depends on depth. 1,000 square feet at 1 inch deep is 3.09 cubic yards. At 4 inches, it is 12.35 cubic yards. At 6 inches, 18.52 cubic yards. At 12 inches, 37.04 cubic yards. Multiply your square footage by depth in inches, then divide by 324.
How many cubic yards of concrete for a 10x10 slab?
A 10 by 10 foot slab (100 square feet) at 4 inches thick needs 1.23 cubic yards of concrete. At 5 inches, 1.54 cubic yards. At 6 inches, 1.85 cubic yards. Use the formula (100 × thickness in inches) ÷ 324. Order 5 to 10 percent extra for spillage.
How many cubic feet are in a cubic yard?
There are 27 cubic feet in one cubic yard (3 feet × 3 feet × 3 feet = 27 cubic feet). To convert cubic feet to cubic yards, divide by 27. To convert square feet to cubic yards, you must first multiply by depth in feet to get cubic feet, then divide by 27 — which is the same as square feet times depth in inches divided by 324.
Related Calculators
- How Many Cubic Feet in a Cubic Yard? — the reverse conversion with full reference table
- Concrete Slab Cost Calculator — concrete volume and total cost for slabs and pads
- Gravel Calculator — gravel volume, cubic yards, and tons by area and depth
- Mulch Calculator — mulch cubic yards, cubic feet, and bag counts
- Topsoil Calculator — topsoil volume for lawns and raised beds
- How Much Does a Yard of Concrete Weigh? — weight per yard, slab, and PSI