Unit Converter
Convert between metric and imperial units instantly.
This tool uses precise mathematical conversion factors defined in a local lookup table. All calculations run on your device with no external API calls.
How Unit Conversion Works
Unit conversion uses a base-unit system. Each unit in a category is defined by its ratio to a base unit (e.g., meters for length). To convert from unit A to unit B, the value is first multiplied by A's conversion factor to get the base value, then divided by B's factor. Temperature conversions use specific formulas: °C = (°F − 32) × 5/9 and K = °C + 273.15.
How Unit Conversion Works▾
Unit conversion uses mathematical relationships between measurement systems. Each unit category (length, weight, temperature, volume, speed, area) has a set of conversion factors relative to a base unit. For example, in the length category, meters serve as the base unit, and all other units (kilometers, miles, feet, inches) have a known multiplication factor to convert to/from meters.
The conversion process follows three steps: (1) Convert the input value from the source unit to the base unit, (2) Convert from the base unit to the target unit. This two-step approach ensures accuracy and allows any-to-any conversion within a category using only N factors instead of N-squared direct conversion pairs.
Temperature is handled differently because the relationship between Celsius, Fahrenheit, and Kelvin is not a simple ratio — it involves both multiplication and addition (F = C * 9/5 + 32). The tool uses specific formulas for each temperature conversion pair.
All conversion factors are hardcoded with high precision to avoid floating-point drift.
Step-by-Step Usage Guide▾
1. Select a category (Length, Weight, Temperature, Volume, Speed, Area).
2. Choose the source unit from the "From" dropdown.
3. Choose the target unit from the "To" dropdown.
4. Enter the value to convert.
5. The result appears instantly.
6. Click the swap button to reverse the conversion direction.
Supported Unit Categories▾
Length: Kilometer, Meter, Centimeter, Millimeter, Mile, Yard, Foot, Inch
Weight: Kilogram, Gram, Milligram, Pound, Ounce, Ton (metric)
Temperature: Celsius, Fahrenheit, Kelvin
Volume: Liter, Milliliter, Gallon (US), Quart, Cup, Fluid Ounce
Speed: km/h, m/s, mph, knot
Area: Square meter, Square kilometer, Square foot, Square mile, Hectare, Acre
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Frequently Asked Questions
How does the unit converter work?▾
Our converter uses standard mathematical formulas to convert between units. All calculations happen instantly in your browser — nothing is sent to any server.
What unit categories are supported?▾
We support length, weight, temperature, area, volume, and speed conversions. Each category includes the most commonly used metric and imperial units.
Is this converter accurate?▾
Yes. We use precise IEEE 754 double-precision floating-point arithmetic for all conversions, which provides accuracy to approximately 15 significant digits.