Unit Converter – Length, Weight, Temperature, Speed, Area

From

Value

Result

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How to Use

Select a Category

Click one of the category tabs at the top — Length, Weight, Temperature, Speed, or Area — to load the relevant unit options. The selectors update instantly to show only the units for that category.

Choose Your Units

Select the "From" unit on the left and the "To" unit on the right from the dropdown menus. Click the swap button between them to instantly reverse the conversion direction.

Enter a Value

Type any number into the value field. The result updates instantly as you type — no button press required. The conversion formula is shown below the result for transparency.

Read the Result

The converted value is displayed in large text. Very large or very small numbers are shown in scientific notation for clarity. Change any input at any time for a fresh conversion.

Frequently Asked Questions

Results are computed using JavaScript's 64-bit floating-point arithmetic (IEEE 754 double precision), giving up to 15–17 significant decimal digits of precision. The output is formatted to 8 significant figures for readability. For scientific or engineering work requiring extreme precision beyond this, dedicated software is recommended.

Temperature conversions are handled separately because temperature scales use offsets, not simple multiplication factors. The tool converts the input to Celsius as an intermediate step, then converts from Celsius to the target scale. Formulas: °F = (°C × 9/5) + 32; K = °C + 273.15. The formula used is displayed below the result for every conversion.

The converter supports: Length — meter, kilometer, centimeter, millimeter, mile, yard, foot, inch, nautical mile. Weight — kilogram, gram, milligram, pound, ounce, metric ton, stone. Temperature — Celsius, Fahrenheit, Kelvin. Speed — m/s, km/h, mph, knot, ft/s. Area — square meter, square kilometer, square mile, square yard, square foot, square inch, hectare, acre.

Scientific notation (e.g., 1.23456e+9) is used automatically when the result is either extremely large (greater than 1 billion) or extremely small (less than 0.0001). This prevents the display of unwieldy strings of zeros while preserving the full precision of the result. For example, converting 1 square mile to square millimeters produces a number with 12 digits, which is more readable in scientific notation.

Yes. The conversion factors used in this tool are based on the definitions established by the International System of Units (SI) and internationally accepted exact values. For example, 1 inch is exactly 0.0254 meters (by international agreement since 1959), 1 mile is exactly 1609.344 meters, and 1 pound is exactly 0.45359237 kilograms. These values are fixed by international treaty and do not change.