About Percentage Calculator

Percentage Calculator is a tool that is meant to be used for two purposes: for solving and learning percentages. The former is obvious: many people need a simple tool that will tell them what is x% of y or how many % of foo is bar. It is so simple that there are literally dozens of sites that do it (mine is way cooler, though :-) ).

The other goal of the site - to help kids learn percentages - is a bit trickier. I designed the calculator with a few ideas in mind:

  1. In a 3-field formula user inputs any 2 of the 3 numbers. The third one is calculated for him.
  2. Calculations are done dynamically as user types in his numbers. There is no need to click on a submit button. This way a student sees what is going on as he/she "constructs" the sentence. Also, it is a very quick process (press a single key and see a new result), thus encourages the student to keep experimenting.
  3. There are four forms-sentences that user can fill in: x% of y is z, z is x% of y, fraction z / y is the same as x% and z is q% decrease/increase from y. While the student fills in one form, all the others are completed for him - this way he/she sees that these sentences are in fact the same (or almost the same in the case of 4th sentence).
  4. Few more related formulas are shown, to further show how provided numbers "work" with each other.
  5. The tool can be easily customized embedded on external websites - it is a good way to add an interactive element to otherwise static online lectures, right?

I am not claiming it is a ground-breaking invention, but I hope it can help students grasp the idea of fractions and percentages and show them how these similar formulas relate to each other.

I am really, really bad at marketing. If you like my tool and feel others might like it too, please blog about it, place a link on your website, spread the news on tweeter, facebook, your favorite discussion board. If you like the tool a lot, scream Per - cen - ta - ge - cal - cu - la - tor - dot - in - fo! from your balcony or - better yet - a rooftop*.

* I bear no responsibility for my visitors' overzealous acts of kindness. Sloppy roof... really?