Free Converters for Units, Time Zones and Data

Convert kilometers to miles, Celsius to Fahrenheit or cups to grams, find the time for a call in another time zone, or turn a Unix timestamp into a readable date. This section collects every converter on the site, from everyday units and clothing sizes to the pressure, energy, power and torque units used in coursework, HVAC and car repair.

Many of the unit converters show the formula or a quick reference chart next to the result, so you can check the math or do it by hand next time. There are also converters for data and files: CSV, JSON, YAML and XML, number bases, Base64, and image and audio formats. Images and audio you convert are processed in your browser and are not uploaded, and there is no signup.

Converting a recipe? The cooking calculators can scale a recipe up or down and convert oven temperatures.

37 free tools in this category. All run in your browser with no signup.

Everyday unit converters

Switch between metric and US units for length, weight, volume, temperature, area and speed. The all-in-one unit converter covers every category on one page if you would rather not pick a specific tool.

Unit ConverterConvert length, weight, temperature, volume, speed, area, time and data units, with the exact formula and a quick reference table for every pair.Length ConverterConvert meters, feet, inches, centimeters, kilometers, miles and nautical miles with exact factors, plus feet and inches to centimeters for heights.Kilometers to Miles ConverterConvert kilometers to miles and miles to kilometers with the exact factor 1.609344, with presets and a chart for 5K, 10K, half marathon and marathon.Weight ConverterConvert kg to lbs, pounds to kilograms, ounces, grams, stone, tons and troy ounces with the exact pound definition, plus stone and pounds to kg.Temperature ConverterConvert Fahrenheit, Celsius and Kelvin in any direction, with the formula for each result, a live thermometer and a chart of common temperatures.Volume ConverterConvert liters, US and UK gallons, cups, quarts, pints, fluid ounces, mL, cc and cubic feet with exact factors and clear US versus UK units.Area ConverterConvert square feet, square meters, acres, hectares, square yards and square miles with exact factors, plus every other area unit shown at once.Speed ConverterConvert mph, km/h, knots, m/s, ft/s and Mach with exact definitions, and see running pace per mile and per kilometer for any speed you enter.

Time zone and timestamp converters

Convert a time between any two time zones with daylight saving time handled for you, see one time in up to five time zones at once when you plan a call, or turn Unix timestamps into dates one at a time or as a whole list.

Time Zone ConverterConvert a time between any two time zones with daylight saving handled.Unix Timestamp ConverterConvert a Unix timestamp to a readable date or a date to epoch time, with seconds and milliseconds detected automatically and UTC or local time.Bulk Unix Timestamp ConverterConvert a list of Unix timestamps or dates in one go.

Cooking measurements and clothing sizes

Turn cups into grams using the density of the actual ingredient, and convert shoe, ring and hat sizes between US, UK, European and other systems before you order from another country.

Cooking Measurement ConverterConvert cups, tablespoons, teaspoons, ounces and mL to grams for 16 common ingredients, with US, metric and Japanese cup sizes and an oven temperature chart.Shoe Size ConverterConvert shoe sizes between US, UK, EU and foot length in cm for men, women and kids, with full size charts and a foot measuring guide.Ring Size ConverterConvert ring sizes between US, UK/AU and EU, or look up your size from inner diameter or circumference in millimeters, with a full chart.Hat Size CalculatorFind your hat size from head circumference in cm or inches, with a full chart of US, UK, European and S to XL hat sizes and measuring tips.

Number, binary and data size converters

Convert numbers between binary, octal, decimal and hexadecimal with the steps shown, translate text to binary and back, write years in Roman numerals, turn decimals into fractions, and convert storage units like GB and GiB.

Number Base ConverterConvert whole numbers between binary, octal, decimal, hex and any base from 2 to 36.Binary to Text ConverterTranslate binary to text and text to binary in UTF-8, with decimal and hex modes for whole numbers.Roman Numeral ConverterConvert numbers from 1 to 3,999 to Roman numerals and back, with a step-by-step breakdown, a 1 to 100 chart and a table of years.Decimal to Fraction ConverterConvert a decimal to a fraction in simplest form and as a mixed number, with steps, repeating decimals, tape-measure sizes and fraction to decimal.Data Storage ConverterConvert bytes, KB, MB, GB, TB, PB and binary KiB to EiB with exact answers, plus megabits for internet speeds.

Data format converters: CSV, JSON, YAML and XML

Reshape data between the formats used by spreadsheets, APIs and config files, with a table preview for CSV, and encode text or files as Base64. To format and validate JSON itself, use the developer tools.

CSV to JSON ConverterConvert CSV to JSON and JSON to CSV in your browser.YAML to JSON ConverterConvert YAML to JSON or JSON to YAML in your browser, with multi-document Kubernetes files, anchors, merge keys and error messages that point to the line.XML to JSON ConverterConvert XML to JSON and JSON to XML with attributes as @keys, repeated tags as arrays, optional number types and errors that give the line and column.TSV to CSV ConverterConvert TSV to CSV and CSV to TSV with correct quoting for commas, quotes and line breaks, a comma or semicolon separator, file open and download.Base64 Decoder and EncoderDecode and encode Base64 online with UTF-8 and URL-safe support, data URI handling and file encoding.

Image, audio, color and speech converters

Convert images between PNG, JPEG and WebP, audio files to MP3 or WAV, and colors between HEX, RGB and HSL. Text to Speech Preview reads text aloud with the voices your browser provides; some browsers also offer online voices, which send the text to that voice provider to speak it.

Image Format ConverterConvert images between PNG, JPG, WebP and BMP in your browser.Audio ConverterConvert MP3, M4A, OGG, FLAC, AAC or WebM audio to WAV or MP3 in your browser, with sample rate, mono or stereo and MP3 bitrate options.Color Picker & ConverterPick a color and convert it between HEX, RGB, HSL, HSB and CMYK.Text to Speech (Read Aloud)Type or paste text and hear it read aloud with your browser's voices, with speed, pitch and volume controls and word highlighting.

Science and engineering unit converters

Pressure, energy, power, torque, frequency, angle, density and acceleration units for coursework, workshop jobs and spec sheets, such as PSI to bar for tires or newton-meters to foot-pounds for a torque wrench.

Pressure ConverterConvert psi, bar, kPa, MPa, atm, mmHg, torr, hPa, inHg and kgf/cm² with exact definitions, for tires, weather, scuba, HVAC and lab work.Energy ConverterConvert joules, kJ, calories, kcal, Wh, kWh, BTU, therms, foot-pounds and eV with exact definitions, and keep food Calories straight from small calories.Power ConverterConvert kW to HP, watts, BTU/h, kcal/h and tons of refrigeration with exact factors, including mechanical, metric and electrical horsepower.Torque Unit ConverterConvert torque between newton-meters, foot-pounds, inch-pounds, kgf·m and more using exact factors, with a quick chart for lug nuts and wrenches.Frequency ConverterConvert Hz, kHz, MHz, GHz, THz, BPM, RPM and rad/s and see the period of each cycle.Angle ConverterConvert degrees to radians, gradians, turns, arcminutes, arcseconds and mils, plus decimal degrees to DMS and the answer as a multiple of pi.Density ConverterConvert density between kg/m³, g/cm³, lb/ft³, lb/gal and specific gravity using exact factors, with a chart of common materials like water and steel.Acceleration ConverterConvert acceleration between m/s², g-force, ft/s², km/h per second and mph per second, and turn a 0 to 60 mph time into average g.

Frequently asked questions

How do I convert Celsius to Fahrenheit?

Multiply the Celsius temperature by 1.8 (or 9/5) and add 32. For example, 20 °C is (20 × 1.8) + 32 = 68 °F. To go the other way, subtract 32 and then multiply by 5/9. The temperature converter does both and also handles Kelvin.

How many ounces are in a cup?

A US cup holds 8 US fluid ounces, about 237 milliliters. Fluid ounces measure volume, not weight, so a cup of flour weighs much less than 8 ounces on a kitchen scale. The cooking measurement converter uses the density of each ingredient to convert cups to grams or ounces by weight.

What is a Unix timestamp?

It is the number of seconds since midnight UTC on January 1, 1970, a moment called the Unix epoch. A 10 digit value is usually in seconds and a 13 digit value is in milliseconds, which is what JavaScript's Date.now() returns. The Unix timestamp converter turns either one into a readable date and back.

Is a gigabyte 1,000 or 1,024 megabytes?

Both are in use. In decimal (SI) units, 1 GB is 1,000 MB, which is how drive makers label capacity. In binary (IEC) units, 1 GiB is 1,024 MiB, which is what Windows counts while still showing the label GB. That is why a 1 TB drive shows up as about 931 GB in Windows. The data storage converter handles both systems.

Guides

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