Calculating 10 per cent of any given number is simple, but when you get into complex percentages or need to calculate reverse percentages things get a little more difficult. Percentage Calculator handles all the maths for you and teaches you how it's done in the process.
The webapp provides you with space to type in whatever part of the equation you know, and it will fill in the blanks. For example, if you know you received $5 this week and that's an 80% decrease from what you received last week, Percentage Calculator can tell you that you received $6.25 last week. It can also convert fractions to percentages.
You may not need these calculations on a regular basis, but it's a good bookmark to have handy when you do.