About the Unit Converter
This unit converter brings ten everyday conversion types together on one page. Pick a category, enter a value and unit, and you get the converted result plus the same value in every unit of that category in the list below.
All calculations use the exact international definitions (1 inch = 2.54 cm, 1 pound = 0.45359237 kg, and so on), and results are rounded to 8 significant digits so floating-point noise like 0.30000000000000004 never shows up.
How to use
- Choose a category at the top: length, weight, temperature and so on.
- Enter a number under Value and pick its unit.
- Pick the unit under Result. Typing in the result box converts backwards.
- Use ⇅ to swap units, and tap any value in the list to copy it.
- Your last value and units are remembered per category in this browser.
Common conversion factors
| Type | Conversion |
|---|---|
| Length | 1 in = 2.54 cm · 1 ft = 30.48 cm · 1 mi = 1.609344 km |
| Weight | 1 lb = 453.59237 g · 1 oz ≈ 28.35 g · 1 kg ≈ 2.2046 lb |
| Area | 1 sq ft ≈ 0.0929 m² · 1 acre = 43,560 sq ft · 1 ha ≈ 2.471 acres |
| Volume | 1 US gal ≈ 3.785 L · 1 imperial gal ≈ 4.546 L · 1 cup ≈ 236.6 ml |
| Temperature | °F = °C × 1.8 + 32 · K = °C + 273.15 |
| Speed | 1 mph ≈ 1.609 km/h · 1 knot = 1.852 km/h · 1 m/s = 3.6 km/h |
| Data | 1 GB = 1,000 MB · 1 GiB = 1,024 MiB · 1 TB ≈ 931.3 GiB |
| Pressure | 1 atm ≈ 14.696 psi · 1 bar = 100 kPa ≈ 14.5 psi |
| Energy | 1 kcal = 4.184 kJ · 1 kWh = 3.6 MJ ≈ 3,412 BTU |
Tire pressure: psi and bar
US cars list tire pressure in psi on the sticker inside the driver’s door; European cars often use bar or kPa. 1 bar = 100 kPa ≈ 14.5 psi, so 35 psi is about 2.41 bar (241 kPa). The Pressure tab starts at 35 psi → bar.
FAQ
How accurate are the results?
Conversions use exact factors from the international definitions, and results are shown to 8 significant digits. Very large or very small numbers are shown in scientific notation, like 1.23 × 10⁻⁷.
What is the difference between a calorie and a kilocalorie?
1 kcal = 1,000 cal. The “Calories” on US food labels are actually kilocalories. This tool uses the thermochemical calorie (1 cal = 4.184 J).
How long is a month or a year here?
A year is the Gregorian average of 365.2425 days and a month is one twelfth of that, about 30.44 days. For the exact number of days between two dates, use a date calculator.
Are there more detailed converters?
Yes. The dedicated length (height in feet and inches), weight, area, temperature (oven chart) and data size (download time) converters offer more units and reference tables.