Assumptions
- 1 ft = 0.3048 m, 1 lb = 0.45359237 kg, 1 US gal = 3.785411784 L (exact definitions).
- 1 pyeong = 400/121 m² = 3.305785 m².
- Results are displayed with 2–6 decimals depending on magnitude.
How it is calculated
Every unit is converted to a base unit (m², m, kg, L) and then to the target: result = value × factor(from) ÷ factor(to). Factors are the defined values with no intermediate rounding.
| Unit | Definition |
|---|---|
| 1 square foot | 0.09290304 m² (exact) |
| 1 acre | 43,560 sq ft = 4,046.8564224 m² (exact) |
| 1 hectare | 10,000 m² = 2.4711 acres |
| 1 inch / foot / mile | 25.4 mm / 0.3048 m / 1,609.344 m (exact) |
| 1 pound / ounce | 453.59237 g / 28.349523125 g (exact) |
| 1 US gallon / imperial gallon | 3.785411784 L / 4.54609 L (exact) |
| 1 pyeong | 400/121 m² ≈ 3.305785 m² |
Examples
| Situation | Input | Result |
|---|---|---|
| 1,500 sq ft house | 1,500 ft² → m² | 139.35 m² |
| Half-acre lot | 0.5 acre → m² | 2,023.43 m² |
| Marathon | 26.2 mi → km | 42.16 km (official: 42.195) |
| Parcel weight | 5 lb → kg | 2.268 kg |
| Recipe | 2 US cups → mL | 473.18 mL |
Common mistakes
- "Cup" varies: a US customary cup is 236.6 mL, the US legal cup on nutrition labels is 240 mL, a metric cup is 250 mL.
- Ounce (weight) vs fluid ounce (volume) are different units; this tool keeps them in separate categories.
- Temperature (°F ↔ °C) is not a simple ratio and is not in this table; it is provided as a separate tool.
FAQ
How many square feet are in a square meter?
10.7639 sq ft. One foot is exactly 0.3048 m, so one square foot is exactly 0.09290304 m². A 1,500 sq ft house is 139.35 m².
Why are US and imperial gallons different?
A US gallon is 231 cubic inches = 3.785411784 L; an imperial (UK) gallon is 4.54609 L — about 20% more. Fuel economy in mpg is not comparable between the two without converting.
What is a pyeong?
A Korean floor-area unit still used informally for apartments: 1 pyeong = 400/121 m² = 3.3058 m² (about 35.58 sq ft). Korean listings legally use m², but "34-pyeong type" is common speech. Japan's tsubo is the same size.
Are the factors exact?
Yes for inch, foot, yard, mile, pound, ounce and US gallon — they are defined exactly by the 1959 international yard and pound agreement and US law. The tool uses those definitions without intermediate rounding; only the displayed result is rounded.
Is anything saved?
No. Conversion runs only in your browser and nothing is transmitted.