Unit Converter
Choose a category, pick the unit you have and the unit you want, then enter a value. The result appears at once with the exact factor behind it, so you can check the arithmetic yourself.
Last updated November 4, 2026
0 or more, up to 1,000,000,000,000.
Result
1 Miles (mi) = 1.609344 Kilometers (km)
| Item | Value |
|---|---|
| Category | Length |
| Result | 1.609344 Kilometers (km) |
| Factor used | 1 Miles (mi) = 1.609344 Kilometers (km) |
Show the work
Formula: result = value × factor, where factor is the amount of the target unit in 1 unit of the source.
- You chose length and entered 1 Miles (mi).
- Factor: 1 Miles (mi) = 1.609344 Kilometers (km).
- Multiply: 1 × 1.609344 = 1.609344 (rounded for display: 1.609344).
Result: 1 Miles (mi) = 1.609344 Kilometers (km)
How the unit converter works
result = value × factor · °F = °C × 9/5 + 32 · K = °C + 273.15
Most units differ by a fixed ratio. 1 mile is exactly 1.609344 kilometers, 1 pound is exactly 0.45359237 kilograms and 1 US gallon is exactly 3.785411784 liters, so a conversion is one multiplication. The page shows that factor under the result.
Area works on squares of the length ratio: 1 foot is 0.3048 meters, so 1 square foot is 0.3048 × 0.3048 = 0.09290304 square meters. Temperature is the exception. Celsius, Fahrenheit and Kelvin start at different zero points, so they use a formula with an offset instead of one factor, and nothing can go below absolute zero.
See how we calculate for the formulas, sources and review schedule behind every calculator.
When to use a dedicated converter
This page is the quick all-in-one option when you jump between kinds of measurement. A single-purpose converter, such as the length, weight, volume or temperature pages, shows every unit of its kind at once and gives longer worked examples and reference tables. Pick one of those when you need the full list or are converting repeatedly in one category.
How to use the Unit Converter
- Select a category: length, mass, volume, temperature, speed or area.
- Choose the unit you are converting from and the unit you want.
- Enter the value; the result and the factor used update as you type.
- Open Show the work to see the factor and multiplication, then Copy, Print or Share.
Worked example
A marathon is 26.2 miles. Multiply by 1.609344 to get 42.1648128 km. In the same way, 70 °F is (70 − 32) × 5/9 = 21.1111 °C, and 100 km/h divided by 1.609344 is about 62.1371 mph. Changing the category resets both units to sensible defaults, so check the From and To boxes after you switch.
| Category | From | To | Factor |
|---|---|---|---|
| Length | 26.2 mi | 42.1648 km | 1.609344 |
| Mass | 150 lb | 68.0389 kg | 0.45359237 |
| Volume | 5 US gal | 18.9271 L | 3.785411784 |
| Temperature | 70 °F | 21.1111 °C | Formula |
| Speed | 100 km/h | 62.1371 mph | 0.621371 |
| Area | 20 m² | 215.2782 ft² | 10.763910 |
Frequently asked questions
Which units can this converter handle?
Six categories: length, mass or weight, volume, temperature, speed and area. Each category offers the units most people use in everyday and trade settings.
Why is there no single factor for temperature?
Celsius, Fahrenheit and Kelvin have different zero points, so converting needs a formula with an offset, such as F = C × 9/5 + 32, not just a multiplication.
Is the US gallon the same as the imperial gallon?
No. A US gallon is 3.785411784 liters and an imperial gallon is 4.54609 liters, about 20 percent larger. Choose the one that matches your source.
Why does the page reject negative values?
Lengths, masses, volumes, speeds and areas cannot be negative here. Only temperature accepts negatives, down to absolute zero at -273.15 °C.