Converters
Free, browser-based unit converters for the measurements you actually look up: length, weight, temperature, speed, pressure, energy, data storage, fuel economy and kitchen quantities. Every conversion is calculated instantly on your device, with no upload step and no waiting for a server to respond.
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Angle Converter
Convert between degrees, radians, gradians, turns, arcminutes and arcseconds.
Try freeCooking Measurement Converter
Convert between cups, tablespoons, teaspoons, milliliters, fluid ounces and liters.
Try freeData Storage Converter
Convert between bits, bytes, KB, MB, GB, TB and PB with binary (1024) and decimal (1000) modes.
Try freeElectricity Cost Calculator
Calculate daily, monthly and yearly electricity cost from watts, hours per day and electricity rate.
Try freeEnergy Converter
Convert between joules, calories, kilocalories, BTU, kilowatt-hours and electronvolts.
Try freeFuel Economy Converter
Convert between MPG (US), MPG (UK), L/100km and km/L with inverse relationship handling.
Try freeLength Converter
Convert between millimeters, centimeters, meters, kilometers, inches, feet, yards and miles.
Try freePressure Converter
Convert between pascals, kilopascals, bar, atmospheres, PSI, mmHg and torr.
Try freeShoe Size Converter
Convert shoe sizes between US, UK, EU and JP sizing systems for men and women.
Try freeSpeed Converter
Convert between km/h, mph, m/s, ft/s and knots.
Try freeTemperature Converter
Convert between Celsius, Fahrenheit and Kelvin with formula display.
Try freeTime Unit Converter
Convert between milliseconds, seconds, minutes, hours, days, weeks, months and years.
Try freeAll-in-One Unit Converter
Master converter with tabs for length, weight, temperature, speed, area and volume.
Try freeWeight Converter
Convert between milligrams, grams, kilograms, ounces, pounds, stone and tons.
Try freeConvert between metric and imperial units
Most everyday conversions come down to bridging the metric and imperial systems, which is exactly what these tools are tuned for. Use the length converter for metres, centimetres, feet, inches, yards, miles and kilometres, and the weight converter for kilograms, grams, pounds, ounces and stone. When you need a single page that handles dozens of categories at once, the all-in-one unit converter covers length, mass, area, volume and more without switching tools.
Common conversion categories
- Length and distance - the length converter handles everything from millimetres to nautical miles.
- Weight and mass - the weight converter moves between grams, kilograms, pounds and stone.
- Temperature - the temperature converter covers Celsius, Fahrenheit and Kelvin with exact formulas, not lookup tables.
- Speed - the speed converter swaps km/h, mph, m/s and knots.
- Time - the time unit converter goes from milliseconds to weeks and years.
Scientific and engineering units
Several converters here go beyond the kitchen and the gym. The pressure converter handles pascals, bar, psi, atmospheres and mmHg for weather, tyres and lab work. The energy converter moves between joules, calories, kilowatt-hours and BTU, and the angle converter switches degrees, radians and gradians. The data storage converter distinguishes decimal and binary prefixes so you can tell a marketing "1 TB" from an operating system's tebibyte, and the fuel economy converter reconciles miles per gallon with litres per 100 km, including the US and imperial gallon difference.
Everyday and practical converters
For the kitchen, the cooking measurement converter turns cups, tablespoons, millilitres and grams into one another so a recipe from another country still works. When shopping across regions, the shoe size converter aligns US, UK, EU and centimetre sizing. And when a number on a meter matters more than the raw unit, the electricity cost calculator turns kilowatt-hours and a tariff rate into a real running cost for an appliance.
Why convert in the browser
Unit conversion is pure arithmetic, so there is no reason to send your numbers to a server. These tools run entirely in your browser using exact conversion factors, which means results appear the moment you type, they work offline once the page has loaded, and nothing about what you are measuring is logged or stored. That makes them quick for a single lookup and reliable for repeated work like converting a whole spreadsheet of values by hand.
Frequently Asked Questions
Which converter should I use for a quick everyday conversion?
For a single value, open the specific converter for that quantity, such as the length converter or temperature converter, type the number and read the result instantly. If you regularly need different categories, the all-in-one unit converter keeps length, weight, volume and more on one page so you do not have to switch tools.
Are the conversions exact or rounded?
The tools calculate with full precision using standard conversion factors, then display a sensible number of decimal places for readability. Temperature uses the exact Celsius, Fahrenheit and Kelvin formulas rather than approximate tables, so a value like 37 degrees Celsius converts precisely.
What is the difference between US and imperial gallons in fuel economy?
A US gallon is about 3.785 litres while an imperial (UK) gallon is about 4.546 litres, so the same litres-per-100-km figure produces a different miles-per-gallon number depending on which gallon you mean. The fuel economy converter lets you pick the gallon type so US and UK figures are not confused.
Does the data storage converter handle binary and decimal sizes?
Yes. It separates decimal units like megabytes and terabytes (powers of 1000) from binary units like mebibytes and tebibytes (powers of 1024). That is why a drive sold as 1 TB shows up as roughly 0.91 TiB in your operating system, and the converter makes that gap explicit.
Do these converters work offline and keep my data private?
Yes. Every converter runs as JavaScript in your browser, so once the page is loaded the calculations happen on your device with no network request. The numbers you enter are never uploaded, logged or stored on ZeroUtil servers.