Unit Converter
Convert between common units of length, weight, and temperature.
What This Unit Converter Does
This tool converts between common units of length, weight, and temperature — useful for cooking, travel, fitness, DIY projects, or schoolwork that mixes metric and imperial units.
How It Works
Length and weight conversions work by converting your value into a common base unit (meters for length, kilograms for weight) and then into your chosen target unit. Temperature conversions use the standard formulas between Celsius, Fahrenheit, and Kelvin.
Frequently Asked Questions
Which units can I convert?
Length supports meters, kilometers, centimeters, millimeters, miles, yards, feet, and inches. Weight supports kilograms, grams, pounds, ounces, and metric tons. Temperature supports Celsius, Fahrenheit, and Kelvin.
How accurate are the conversions?
The calculator uses standard, internationally recognized conversion factors and rounds results to five decimal places.
Can I convert between length and weight?
No — length and weight are different physical quantities and cannot be converted into one another. Use the matching tab for the type of unit you're converting.
How to check this result
Choose the correct source and destination units before entering a value.
Method and assumptions
Conversions use fixed relationships between units, such as centimetres per metre or grams per kilogram.
Before making a decision
Temperature conversions are different because they use an offset as well as a multiplier.
Conversion factors and temperature offsets
Method
Choose the source and target units within the same measurement type. Length and mass conversions use fixed factors. Temperature requires an offset as well as a factor: °F = °C × 9/5 + 32.
Worked example
One international mile is exactly 1.609344 kilometres. A mass of 2 pounds is 0.90718474 kilograms. A temperature of 20°C is 68°F, because 20 × 1.8 + 32 = 68.
Limitations
Mass and volume are not interchangeable without density. A cup of water and a cup of flour do not have the same mass. Do not use the temperature formula for a temperature difference: a change of 10°C is a change of 18°F.
Why do reverse conversions differ slightly?
Displayed values are rounded. Retain full precision in intermediate steps and round only the final result when converting back.
2026-10-03
Reference for checking the method
Use a conversion factor for the same physical quantity; temperature scales also need an offset.
This reference explains the concept; its publisher has not verified or endorsed this calculator.