Unit Converter
One converter for every conversion a student actually needs: length, mass, temperature, area, volume, time, speed, energy, power, pressure, frequency, voltage, current and resistance. Pick a category, search for your unit, and the result updates instantly — with the reverse conversion shown too.
100 km =
62.13711922 mi
Reverse: 100 mi = 160.9344 km
How it works
- Choose a category (Length, Temperature, Energy, Voltage …).
- Pick the source unit and target unit from searchable lists.
- Type a value — the converted result appears instantly.
- The reverse conversion (target → source) is shown at the same time.
- Temperature uses proper offset math (32 °F is 0 °C, not −17.8 °C of error).
The formula
Linear conversions
value × factor₁ × (1 ÷ factor₂)
Most units convert through a shared base unit (e.g. meters, kilograms, joules) using fixed conversion factors.
Temperature (offset conversions)
°F = °C × 9/5 + 32 · K = °C + 273.15
Temperature scales have different zero points, so they need an offset — not just a multiplier.
Worked example
Worked example
- Convert 100 km/h to mph.
- 1 km/h = 0.621371 mph.
- 100 × 0.621371 = 62.14 mph.
100 km/h ≈ 62.1 mph — the speed limit on many European motorways.
Common mistakes
- Treating temperature like a ratio — “twice as hot” doesn't work in °C or °F; only Kelvin is a true ratio scale.
- Confusing US gallons with imperial gallons — they differ by about 20%.
- Mixing kW and kWh: kW is power (rate), kWh is energy (amount).
Frequently asked questions
How many units does the converter support?
Over 90 units across 14 categories — everything from millimeters and miles to pascals, horsepower and milliohms.
Is the conversion accurate?
Yes. All factors are standard international definitions (e.g. 1 inch = 25.4 mm exactly) and the math is unit-tested.
Does it handle temperature correctly?
Yes — Celsius, Fahrenheit and Kelvin use offset-based formulas, so 0 °C = 32 °F = 273.15 K exactly.
Can I convert between electrical units?
Yes — voltage (mV/V/kV), current (µA/mA/A) and resistance (mΩ/Ω/kΩ/MΩ) are included, which covers most lab work.
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