Unit Converter

Unit Converter implements each conversion as a pure JavaScript multiplication or affine transformation against a base unit per category. Length normalizes to meters, weight to kilograms, volume to liters, area to square meters, speed to meters-per-second, time to seconds, and data storage to bytes. The conversion factors are hardcoded constants from the SI brochure and NIST handbook, so a meter-to-foot conversion uses 3.28084, not a runtime lookup.

Temperature is the exception — it requires affine (offset) transformations because the zero points of Celsius, Fahrenheit, and Kelvin are different. Celsius to Fahrenheit uses (C × 9/5) + 32; Celsius to Kelvin uses C + 273.15. The tool special-cases temperature math rather than using a single base-unit factor approach.

All math uses standard JavaScript Number arithmetic, which is IEEE 754 double-precision floating point. This gives about 15-17 significant decimal digits of accuracy — sufficient for any practical engineering or cooking conversion. Some conversions like 1 inch = 2.54 cm are exact under the 1959 international yard agreement; others like miles to nautical miles introduce a small rounding error far below practical relevance.

Data storage units have a notorious gotcha: kilobyte, megabyte, gigabyte, and terabyte are ambiguous. Decimal (SI) interpretation defines 1 KB = 1000 bytes; binary (IEC) defines 1 KiB = 1024 bytes. Hard drive manufacturers use decimal; RAM manufacturers and operating systems often use binary. This tool exposes both decimal and binary units explicitly so you can pick the right interpretation for your context.

Volume conversions hide another trap: a US fluid ounce (29.5735 mL) differs from a UK/Imperial fluid ounce (28.4131 mL) by about 4%, and a US cup (236.588 mL) differs from a metric cup (250 mL) and an Imperial cup (284.131 mL). For recipes, always check whether the source uses US or metric measurements — this tool labels them distinctly.

The 'All conversions' panel computes every target unit in the selected category in a single render pass. Because each conversion is a single multiplication or affine transform, all 70+ unit conversions complete in well under a millisecond — fast enough to run on every keystroke.

Everything is computed locally; no value you enter is logged, transmitted, or persisted. The tool is a pure-function calculator that runs entirely in your browser tab.