Unit Converter Tools
Instant unit converters for temperature, length, weight, speed, volume, storage, area, and percentages. Type in any field and all other units update immediately.
Temperature Converter
Convert between Celsius, Fahrenheit, Kelvin, and Rankine — edit any field and all others update instantly.
Length & Distance Converter
Convert between kilometres, miles, feet, metres, inches, yards, and nautical miles simultaneously.
Weight & Mass Converter
Convert kilograms, pounds, ounces, stones, grams, and metric tons in one place.
Volume Converter
Convert litres, US gallons, cups, pints, quarts, and fluid ounces — metric and imperial side by side.
Speed Converter
Convert mph, km/h, m/s, knots, ft/s, and Mach — useful for travel, aviation, and physics.
Data Storage Converter
Convert bytes, KB, MB, GB, TB, PB, bits, and megabits — essential for storage and networking.
Area Converter
Convert square metres, square feet, acres, hectares, and square miles for any land or property calculation.
Percentage Calculator
Find X% of a number, calculate what percentage one number is of another, or compute percentage change.
Unit Conversion: The International System of Units
All converters on this page use the International System of Units (SI), maintained by the Bureau International des Poids et Mesures (BIPM) in Sèvres, France, and adopted by the National Institute of Standards and Technology (NIST) in the United States. SI defines seven base units from which all others derive: the metre, kilogram, second, ampere, kelvin, mole, and candela. Conversion factors between SI units and imperial units are exact by international agreement — 1 inch is exactly 25.4 millimetres, defined since 1959.
When Precision Matters
For everyday cooking, construction, or travel, three significant figures are sufficient. For engineering, chemistry, or scientific work, be aware of floating-point precision limits in browser calculations. The conversions here use standard double-precision floating-point arithmetic (IEEE 754), which provides about 15-17 significant decimal digits of precision — more than sufficient for any practical application. If you need arbitrary-precision arithmetic for scientific computation, use a dedicated scientific computing library.
Binary vs. Decimal Units for Data Storage
Data storage is a special case where two competing unit systems coexist. Hard drive manufacturers use decimal prefixes (1 GB = 1,000,000,000 bytes), while operating systems historically used binary prefixes (1 GB = 1,073,741,824 bytes). The IEC standardized binary prefixes in 1998 — kibibyte (KiB), mebibyte (MiB), gibibyte (GiB) — to remove ambiguity. Our data storage converter clearly labels which system is being used for each unit.
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