Universal Unit Converter
Convert length, mass, area, volume, speed, temperature, pressure, energy, data, and time with configurable precision.
All conversions in this category
Enter a value to see it converted into every unit in this category.
How to use the Unit Converter
- 1
Select one of the ten conversion categories from the tabs.
- 2
Enter a numeric value in the 'From' field and select its unit from the dropdown.
- 3
Select the target unit in the 'To' dropdown — the converted value appears instantly.
- 4
Use the ⇄ Swap button to quickly reverse the conversion direction.
Features
- ✓10 categories: length, mass, area, volume, speed, temperature, pressure, energy, data size, and time.
- ✓Special temperature logic: Uses °C as the base with formulas °F = °C × 9/5 + 32 and K = °C + 273.15 for precision.
- ✓Controlled display precision: Rounds output to 10 significant digits so ordinary binary floating-point artifacts are less distracting; it does not change the underlying calculation precision.
- ✓Swap button: Instantly exchange From and To units to quickly reverse any conversion.
FAQ
Q. What temperature formula is used?
A. Celsius (°C) is the base unit. Fahrenheit: °F = °C × 9/5 + 32. Kelvin: K = °C + 273.15. Absolute zero is −273.15°C = 0K = −459.67°F.
Q. What is the difference between kB and KiB?
A. kB is decimal (1 kB = 1000 B), while KiB is binary (1 KiB = 1024 B). This tool exposes both as separate units.
Q. Can you add more units?
A. Feel free to request additional units via the contact page. High-demand units will be considered for future additions.
Q. Why do I sometimes see floating-point rounding in results?
A. Calculations use JavaScript IEEE 754 double-precision numbers. toPrecision(10) formats the displayed result to 10 significant digits; it reduces visible artifacts but does not eliminate underlying floating-point error.
Q. Can you add cooking units like cups, tablespoons, or teaspoons?
A. Yes. The Volume category includes US tsp, US tbsp, and US cup. The US prefix is shown because cooking measures differ by country.
Technical Deep Dive: Unit Conversion Architecture & Floating-Point Precision
Length and weight conversions use a hub-unit conversion table approach: every unit is defined by its conversion factor relative to an SI base unit (meter for length, kilogram for weight). For example, 1 inch = 0.0254 m and 1 mile = 1609.344 m are exact defined values. Converting from unit A to unit B is computed as: value × (A's factor to base) / (B's factor to base). This architecture requires only N coefficients for N units rather than an N×(N-1) pairwise lookup table, keeping the implementation compact and easy to extend.
Temperature conversion cannot be represented as a simple multiplicative factor because it involves a translational (affine) component. This tool normalises all temperatures through Celsius (°C) as the intermediate pivot. The formulas are: °F to °C: (°F − 32) × 5/9; K to °C: K − 273.15; and their inverses. Converting from Fahrenheit to Kelvin is therefore a two-step process: °F → °C → K, ensuring accuracy without error accumulation.
JavaScript uses IEEE 754 double-precision floating-point arithmetic, which produces familiar artifacts such as 0.1 + 0.2 = 0.30000000000000004. The tool formats results with up to 10 significant digits for readability; this is output rounding, not a higher-precision arithmetic engine.
Data size conversion distinguishes SI decimal prefixes (kB, MB, GB) from IEC binary prefixes (KiB, MiB, GiB). The symbols look similar but use different factors, so both families are available explicitly.
Data Handling & Security Notes
Unit conversion performs pure arithmetic on a numeric value entered by the user. Input is captured by React's onChange handler and processed entirely within local JavaScript functions. No API calls or network requests are made at any point.
Numeric inputs — including personal measurements such as body weight or height — never leave the browser. Values exist only in component state and are discarded when the page is closed. This service collects no data from the unit converter.