Unit Converter FREE

Convert units of length, weight, area, volume, speed, energy, pressure, and data size online free. Instant results. No sign-up. Runs entirely in your browser.

Length

Weight

Area

Volume and More

Unit Converter

Frequently Asked Questions

All conversions use internationally recognised standard conversion factors. Length, weight, volume, and area use SI base units. Temperature conversions use the exact formula. Data size uses base-2 (binary) prefixes for kibibyte, mebibyte etc. For scientific and engineering work, results are accurate to 10 significant figures.

Length (metres, feet, miles, inches, cm, km, yards, nautical miles), Weight (kg, pounds, ounces, grams, tonnes, stone), Area (sq metres, sq feet, acres, hectares, sq miles, sq km), Volume (litres, gallons, pints, cups, fluid ounces, millilitres, cubic metres), Speed (km/h, mph, m/s, knots), Temperature (Celsius, Fahrenheit, Kelvin), Energy (joules, calories, kWh, BTU, electronvolts), Pressure (Pa, bar, psi, atm, mmHg), Data Size (bits to petabytes), and Time (seconds to centuries).

Yes. Temperature is included as a category. The converter handles the non-linear Celsius to Fahrenheit formula (F = C x 9/5 + 32), the Celsius to Kelvin formula (K = C + 273.15), and the reverse conversions correctly, not just a multiplication factor.

No limit. JavaScript handles numbers up to 1.8 x 10^308. For very large or very small numbers, results are displayed in scientific notation automatically.

Results are shown with up to 10 significant figures. Very small or very large values are shown in scientific notation for readability. The raw precision depends on JavaScript floating-point arithmetic.

About One Doc Studio

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Free Online Unit Converter — Convert Length, Weight, Area, Volume, Speed and More

Unit conversion is one of the most universally needed calculations in science, engineering, cooking, travel, construction, and everyday life. The Unit Converter on OneDocPDF handles ten major measurement categories covering the units used in every professional and personal context. Every conversion runs instantly in your browser using JavaScript, with no server roundtrip, no waiting, and no installation required. The conversion factors used are sourced from the International Bureau of Weights and Measures (BIPM) and the National Institute of Standards and Technology (NIST) to ensure accuracy across all categories.

Engineers converting between imperial and metric systems for international projects, chefs adapting recipes from American cup measurements to metric weights, travellers converting between miles and kilometres, and students verifying physics homework all rely on fast, accurate unit converters. This tool provides all ten most commonly needed categories in a single clean interface. The temperature category correctly handles the non-linear Celsius-Fahrenheit-Kelvin conversions rather than applying a simple multiplication factor. The data size category uses both decimal (SI) and binary (IEC) prefixes to distinguish between megabytes (1,000,000 bytes) and mebibytes (1,048,576 bytes) as used in computing.

OneDocPDF offers a full suite of complementary tools. Use our Scientific Calculator for complex calculations, our Percentage Calculator for proportional calculations, and our Age Calculator for date-based computations. For document workflows, our JPG to PDF tool and Image Compressor handle all your file conversion needs.