Universal Unit Converter
Convert length, weight, temperature, and data storage units in real time. Covers both metric and imperial systems.
How to use the Unit Converter
- 1
Select a category from the tabs at the top: Length, Weight, Temperature, or Data Size.
- 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
- ✓4 categories: Length (mm–miles), Weight (mg–tonnes), Temperature (°C/°F/K), Data Size (B–PB).
- ✓Special temperature logic: Uses °C as the base with formulas °F = °C × 9/5 + 32 and K = °C + 273.15 for precision.
- ✓High-precision results: Uses toPrecision(10) to minimize floating-point errors in conversion calculations.
- ✓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. Is 1 KB equal to 1000 B or 1024 B?
A. This tool uses the binary (computing) standard: 1KB = 1024B, 1MB = 1024KB (= 1,048,576B). This differs from the decimal standard (1KB = 1000B) used by some storage manufacturers.
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. All calculations use JavaScript's IEEE 754 double-precision floating-point numbers. The tool applies toPrecision(10) to minimize visible rounding, but very small residuals may occasionally appear. This is a known property of binary floating-point arithmetic, not a bug.
Q. Can you add cooking units like cups, tablespoons, or teaspoons?
A. Volume units for cooking are not yet supported. The weight category covers standard SI units. Cooking volume units are on the roadmap — feel free to request them via the contact page.
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 (64-bit: 52-bit mantissa + 1 implied bit = 53 bits of precision). This causes familiar artefacts like 0.1 + 0.2 = 0.30000000000000004. The tool applies toPrecision(10) to all results, rounding to 10 significant figures and eliminating visually distracting residuals in the vast majority of practical conversions.
Data size conversions follow the IEC 80000-13 binary standard: 1 KB = 1024 B = 2¹⁰ B, 1 MB = 1024 KB = 2²⁰ B, and so on. This differs from the SI/decimal standard (1 KB = 1000 B) used by many storage manufacturers when labelling hard drives — which is why a '1 TB' drive appears as approximately 931 GB in an operating system that uses the binary standard.
Security & Privacy Guarantee
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.