About Percentage Calculator
Percentage calculator is a website which provides multiple well-polished calculators that solve various problems related to percentages. It originated as a single tool (which is now called the advanced mode). As the time passed, I added a few specialized tools, which let users calculate simple percentages, percentage increase and decrease, restaurant tip, store discount, markup, profit margin and convert fractions to percentages.
All these calculators are carefully crafted - users can enter any two fields of any equation and the 3rd is calculated. For example in "x/y is the same as z%" you may enter either x and y, y and z or x and z. Other unique quality is that everything is calculated on the fly, just as you type. Try the demo on the right to see it for yourself.
Percentage Calculator serves two purposes. The obvious one is simply letting people find out answers to their percentage-related questions. The other one is to helps kids learn. The general idea is that when kids input some numbers, they see how they impact other fields in the same sentence AND how different sentences relate to each other - they are in fact the same formula expressed in a slightly different way. The website is full of short "lectures" (I know, the word is a bit too big) accompanied by examples and interactive calculators.
The calculator can be freely customized and embedded on external websites. This way it can be used as an interactive toy on online math courses or an useful utility wherever (someone just suggested on twitter that Google should use it on AdWords website :-) ).
About the Percentage Calculator mobile app
The Percentage Calculator Android app has exactly the same functionality as the web counterpart, only is optimized for smaller screens and is available in several languages. At the time of writing this document English, Spanish, French, Portuguese, Italian, German, Polish and Arabic versions are available. Japanese, Traditional Chinese, Korean and Thai are being prepared.
In the 2.5 months on Google Play it was installed by over 15000 people. It is steadily growing in popularity (438 installs yesterday). It was featured among top 10 new apps in tools category in Poland (I don't think I can check these statistics in other countries).
About the author
Mateusz Mucha is a 40 years old web / mobile freelance developer from Krakow, Poland who feels weird when writing about himself in 3rd person. He thinks anything that begins with the word open or free is great. Together with his wife Kasia, they have a daughter Hania, who is quite possibly the awesomest person south of the North Pole.