Free Unit Converters
Convert between units of measurement instantly. Weight, length, temperature, currency, speed, volume, pressure, energy, and more โ all free, all accurate, all in your browser.
Most Popular
Convert kilograms, pounds, ounces, stones, grams, and tonnes. Metric and imperial.
Convert metres, feet, inches, kilometres, miles, yards, and nautical miles.
Convert Celsius, Fahrenheit, and Kelvin with visual thermometer and formula display.
Convert 150+ world currencies with live exchange rates updated throughout the day.
Convert km/h, mph, m/s, knots, and the speed of light and sound.
Convert litres, gallons, cups, millilitres, pints, quarts, and fluid ounces.
Science & Engineering
Convert Pascal, bar, PSI, atm, mmHg, torr, and other pressure units.
Convert joules, calories, kWh, BTU, electronvolts, and foot-pounds.
Convert watts, kilowatts, horsepower, BTU/h, and other power units.
Convert hertz, kilohertz, megahertz, gigahertz, and RPM.
Convert degrees, radians, gradians, arcminutes, and arcseconds.
Convert bytes, KB, MB, GB, TB, PB, bits, and data transfer rates.
Everyday & Lifestyle
Convert cups, tablespoons, teaspoons, ml, and common cooking measurements.
Convert oven temperatures between Celsius, Fahrenheit, and gas marks.
Convert clothing sizes between US, UK, EU, and international standards.
Convert shoe sizes between US, UK, EU, and cm for men, women, and children.
Convert mpg, km/l, l/100km and compare fuel efficiency across standards.
Convert seconds, minutes, hours, days, weeks, months, and years.
Specialist
Convert square metres, acres, hectares, square feet, and square miles.
Convert between binary, octal, decimal, and hexadecimal number systems.
Convert Arabic numbers to Roman numerals and vice versa (I, V, X, L, C, D, M).
Convert gold and silver weights between troy ounces, grams, and pennyweight.
Calculate body fat percentage and lean mass from measurements.
Sports & Fitness
Convert between min/km, min/mile, km/h, and mph. Estimate race finish times.
Calculate cycling speed, distance, and time. Compare cadence and gear ratios.
About Our Unit Converters
xConvert24 provides 25 free unit converters that cover every common measurement need. Each converter is designed for speed and accuracy โ enter a value, select your units, and get the result instantly. There is no page reload, no waiting for a server response, and no sign-up required. Whether you are a student working on physics homework, a chef adapting an American recipe to metric measurements, a traveller comparing fuel economy standards, or an engineer calculating pressure differentials, we have you covered.
How Our Converters Work
Every converter on xConvert24 performs calculations client-side in your browser using standard conversion factors. This means your data never leaves your device โ there is no server processing, no API calls for basic conversions, and no risk of your sensitive measurements being logged anywhere. The only exception is the currency converter, which fetches live exchange rates from a public API to ensure you get the most up-to-date rates available.
Metric vs Imperial: A Global Challenge
The world uses two primary measurement systems: the International System of Units (SI, commonly called metric) and the imperial/US customary system. Only three countries โ the United States, Liberia, and Myanmar โ have not officially adopted the metric system as their primary standard. This creates a constant need for conversion in international trade, travel, cooking, engineering, and everyday communication. Our converters bridge this gap effortlessly, supporting both systems across every measurement category.
Categories Explained
The Most Popular section includes the six converters used most frequently by our visitors: weight (kilograms to pounds is the single most common conversion worldwide), length (metres to feet), temperature (Celsius to Fahrenheit), currency (with live rates), speed, and volume. These cover roughly 80 percent of all conversion needs.
The Science and Engineering section handles professional-grade conversions: pressure for HVAC technicians and meteorologists, energy for physicists and nutritionists (joules to calories), power for electrical engineers, frequency for radio and electronics work, angles for surveyors and game developers, and data storage for IT professionals comparing storage capacities and transfer speeds.
The Everyday and Lifestyle section focuses on practical daily needs. The cooking converter helps home cooks translate American cup measurements into millilitres. The oven temperature converter handles the perennial Celsius-to-gas-mark question for British baking. Clothing and shoe size converters are essential for international online shopping where sizing standards differ between the US, UK, EU, and Asian markets. The fuel economy converter helps drivers compare vehicles rated in different standards (mpg vs l/100km).
The Specialist section includes niche converters for specific fields: precious metals for jewellers and investors who need troy ounce conversions, number base conversions for programmers working with binary and hexadecimal, Roman numerals for historians and students, and body composition calculations for fitness professionals.
The Sports and Fitness section helps athletes and coaches convert between pace and speed formats used in different regions. Runners in the UK think in min/mile while European runners use min/km โ our running pace calculator converts seamlessly between them and estimates race times for 5K, 10K, half marathon, and full marathon distances.
Accuracy and Precision
All conversion factors used in our tools follow internationally recognised standards published by organisations like NIST (National Institute of Standards and Technology), ISO, and the BIPM (Bureau International des Poids et Mesures). Results are displayed to a precision appropriate for the measurement type โ typically 4 to 6 significant figures. For scientific work requiring higher precision, the exact conversion factors are documented in the formula section of each converter.
Looking for Calculators and Other Tools?
If you need calculators (BMI, loan, scientific), time tools (world clock, timezone converter, stopwatch), creative tools (color picker, image editor), or security utilities (password generator), visit our Tools directory. We also have a dedicated Timezone Converter for scheduling across regions with full daylight saving time support.