÷
=
Result
Enter two values to calculate the third
Why Cubic Feet Don't Convert to Square Feet Directly
Cubic feet measure volume (length × width × height), while square feet measure area (length × width). They describe different physical quantities, so there's no single fixed factor between them, unlike inches to centimeters.
What links them is a third dimension thickness or depth. Once that's known, the calculation is exact and simple, which is exactly what site teams need when a supplier quotes sand, aggregate, or concrete in cubic feet (cft) but the layout or brief is in square feet.
The Formula
Volume (cu.ft) = Area (sq.ft) × Thickness (ft)
Rearranged, this gives you whichever value you're solving for on site:
- Area = Volume ÷ Thickness — how much area a known volume of material will cover
- Volume = Area × Thickness — how much material you need for a known area
- Thickness = Volume ÷ Area — what depth a known volume will give across a known area
Since thickness on Indian sites is usually quoted in inches, this tool lets you enter it in inches or feet and converts internally so the math stays accurate.
Area Covered per Cubic Foot at Common Thicknesses
| Thickness | Area per 1 cu.ft | Volume needed per 100 sq.ft |
|---|---|---|
| 1 inch | 12 sq.ft | 8.33 cu.ft |
| 2 inches | 6 sq.ft | 16.67 cu.ft |
| 4 inches | 3 sq.ft | 33.33 cu.ft |
| 6 inches | 2 sq.ft | 50 cu.ft |
| 8 inches | 1.5 sq.ft | 66.67 cu.ft |
| 12 inches (1 ft) | 1 sq.ft | 100 cu.ft |
Frequently Asked Questions
You can't convert volume to area with a fixed factor, because they measure different things. Instead divide the volume (cu.ft) by the thickness or depth in feet to get the area in square feet: Area = Volume ÷ Thickness.
1 cubic foot at 1 inch (1/12 ft) thickness covers 12 square feet, since 1 ÷ (1/12) = 12.
You need about 166.67 cubic feet, since Volume = Area × Thickness = 500 sq.ft × (4/12) ft = 166.67 cu.ft.
Cubic feet, shortened to cft on site, remains the common trade unit for sand, aggregate, and bricks in much of India, even though drawings and plot sizes are usually quoted in square feet or square meters — which is why a thickness-based converter between the two is useful.