Tools
Converters
Fast, accurate unit converters for length, weight, temperature, speed, volume, area and digital storage. Instant results with a full conversion table.
Nine converters covering the units people switch between most: temperature, length, weight, speed, volume, area and data storage, plus currencies and Roman numerals. Each converter page carries a reference table so the common values are visible without typing anything.
Temperature Converter
Converters
Convert between Celsius, Fahrenheit and Kelvin.
Open toolLength Converter
Converters
Convert cm, inches, feet, meters, miles and more.
Open toolWeight Converter
Converters
Convert kg, lbs, grams, ounces and stone.
Open toolSpeed Converter
Converters
Convert mph, km/h, m/s, knots and ft/s.
Open toolVolume Converter
Converters
Convert liters, gallons, ml, cups and more.
Open toolArea Converter
Converters
Convert square meters, feet, acres and hectares.
Open toolData Storage Converter
Converters
Convert bytes, KB, MB, GB and TB.
Open toolCurrency Converter
Converters
Convert currencies with live daily exchange rates.
Open toolRoman Numeral Converter
Converters
Convert numbers to Roman numerals and back.
Open toolExplore
113 tools. Zero uploads. One place.
Every tool opens instantly, works on your phone and keeps your files on your device.
Exact factors, not approximations
The physical-unit converters use the exact definitions fixed by international agreement — an inch is exactly 2.54 cm, a pound is exactly 0.45359237 kg, a mile is exactly 1,609.344 m — and derive every other factor from those. A converter that stores a rounded factor such as 0.454 kg per pound is wrong by about a tenth of a percent, which shows up as soon as you convert a few hundred kilograms. The data storage converter uses decimal units (1 GB = 1,000 MB), the convention disk and phone makers use; the tool page explains why Windows reports the same drive as smaller, using 1,024-based units.
Converter or dedicated page?
The converter tools handle any pair of units in their family. For the most searched pairs — cm to inches, kg to lbs, Celsius to Fahrenheit, km to miles and a few dozen more — there are also dedicated pages with a full table and the formula explained, linked from each converter. Use the dedicated page when you want to look something up; use the converter when you have a specific number.
Currency rates
Currency is the only converter that cannot be exact, because rates move. The currency converter states where its rates come from and when they were last refreshed on the tool page itself, and the figure it shows is a mid-market rate: the rate your bank or card applies will include a margin on top.
Frequently asked questions
How many decimal places do the converters show?
Enough to be useful for the unit involved — typically four significant figures for everyday units — with the full-precision value available by copying the result. Rounding happens at display time only.
Can I convert between imperial and metric in one step?
Yes. Every converter lists both systems in the same dropdown, so feet to metres or gallons to litres is a single conversion, not two.