Square Feet to Cubic Meters (ft² to m³) — Slab Volume Calculator
Common slab thickness
Material (optional) — shows mass
Volume
100 ft² × 4 in = 33.33 ft³ ≈ 0.944 m³
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Quick reference: 100 ft² at common slab thickness
Thickness
Volume (m³)
Volume (yd³)
Concrete (US ton)
1"
0.236
0.309
0.624
2"
0.472
0.617
1.249
3"
0.708
0.926
1.873
4"
0.944
1.235
2.498
6"
1.416
1.852
3.747
8"
1.888
2.469
4.996
12"
2.832
3.704
7.493
Frequently asked questions
Square feet (ft²) measure area, while cubic meters (m³) measure volume. To go from area to volume you must multiply by a third dimension — the slab thickness or depth. Formula: V (m³) = A (ft²) × t (ft) × 0.0283168. The calculator above accepts thickness in inches, feet, centimeters, millimeters or meters and handles the conversion for you.
100 ft² × 4 in = 100 × (4/12) ft = 33.33 ft³ ≈ 0.944 m³. That is also ≈ 1.235 cubic yards. For a standard residential 4-inch concrete slab covering 100 ft², you would order roughly 1.25 yd³ of ready-mix.
Roughly 1.235 yd³. Concrete is sold in cubic yards in the US, so most contractors round up to the nearest quarter or half yard to allow for spillage and uneven ground. For 100 ft² at 4″ you would typically order 1.5 yd³.
Standard ready-mix concrete weighs about 2,400 kg per cubic meter (2.4 metric tons, or about 5,300 lb). Lightweight concrete is closer to 1,600–1,800 kg/m³. Pick "Concrete" in the Material dropdown above to see mass output in kg, metric tons, lb and US short tons.
Typical recommendations: 4 inches for residential floors, patios and walkways; 5–6 inches for garage floors and driveways with passenger vehicles; 6–8 inches for driveways with heavy vehicles or RV parking. Always reinforce with rebar or fibre mesh for slabs above 4 inches.
1 yd³ ≈ 0.7646 m³, and 1 m³ ≈ 1.308 yd³. Because US ready-mix is ordered by the cubic yard, the calculator displays both units in the conversion chips below the main result.
Results are approximate. Verify quantities and densities against supplier specifications before ordering materials.
How the ft² to m³ converter works
This calculator converts an area in square feet (ft²) into a volume in cubic meters (m³) by multiplying by a slab thickness. Enter the area, pick a thickness in inches (default), feet, centimeters, millimeters, or meters, and the result updates instantly. The output panel also shows cubic yards (yd³), cubic feet (ft³), US gallons, and liters — handy when ordering ready-mix concrete, gravel, or topsoil.
Pick a material (concrete, gravel, sand, topsoil, mulch, mortar, water) to add a mass output in kilograms, metric tons, pounds, and US short tons. One-tap presets for 1″, 2″, 3″, 4″, 6″, 8″, and 12″ slab thickness cover the most common residential and commercial use cases. Example: 100 ft² × 4″ ≈ 0.944 m³ ≈ 1.235 yd³ ≈ 2.5 US tons of standard concrete.