About Convert-Top

Convert-Top is a free unit converter and measurement reference covering 127 categories, from everyday length, weight, temperature and cooking measures to scientific, engineering, historical and regional units, as well as shoe, clothing and ring sizes.

Every unit has its own page explaining what it is, how it is defined, where it sits among related units and what it is used for, alongside converters, formulas and tables for every pair of units in its category.

How we check conversions

Conversion factors come from the official definitions of each unit: the International System of Units (SI) as published by the BIPM, NIST publications, and international agreements such as the 1959 international yard and pound agreement. Where a unit has more than one definition (the US and imperial gallon, several calories and BTUs), each version has its own page and says which one it uses.

Historical and regional units varied over time and from place to place; for those we use the most widely cited modern equivalent and say so on the unit's page. Cooking conversions between cups and grams depend on how an ingredient is measured, and clothing and shoe sizes vary by brand, so those pages give standard reference values and explain their limits.

How the site is funded

Convert-Top is free to use and is supported by advertising served by Google AdSense. Ads are kept separate from converters and answers and are clearly labeled. See our Privacy Policy for how advertising and analytics work and how to control them.

Found a mistake or missing unit? We are always extending the site and appreciate corrections.