Calculator finds solutions to common percentage problems. It's done in easy way: more like stories and everyday situations, less like math language.

1. Basics:

% is equal to
1.2. The number
is equal to
1.3. The fraction
is equal to
% from the number

2. Shopping:

2.1. The bike was at a price of
$. Next, its price has been raised by
%. After that, the bike costs
525 $
2.2. I'm a regular customer in The Shop and I obtained
% discount for future shopping. Regular price of washing machine is
$, but I will pay only
800 $
2.3. Yeah! There is a promotion this week - it's
% discount for all products. Some nice handbag costs
$ now. It means, the same handbag was at a price of
58.82 $ (58 $ and 82 cents)
2.4. The mobile phone costs
$ in first shop and
$ in another one. It means that, price offered by second shop is
20% higher

3. Bills:

3.1. My usual electricity bill is about
$ per month. Unfortunately, the bold man in TV was talking about upcoming increase of electricity price by
%. It means I will pay
151.5 $ (151 $ and 50 cents)
each month which is
1.5 $ (1 $ and 50 cents)
3.2. The landlord increased my rent by
$. Before that, I was paying
$ to him. This means my rent has grown by
3.3. My monthly gas bill is
$ in average. It turned out, that I would pay
$ when I switch to another supplier. It will be
20% less

Some facts

  • One percent (1%) is equal to fraction 1/100 or 0,01.
  • To convert some number into percent, you need to convert it to fraction with 100 denominator first. Then, nominator of fraction will tell you "number of percents". For example fraction 3/4 after converting to denominator 100 is equal to 75/100, so it's equal to 75% (simply 3/4 = 75%).
  • If you need to calculate a percent of a number, you have to multiply that number by a proper fraction with 100 denominator. For example 50% from number 10 is equal to 50/100 × 10 = 5.
  • The concept of percentage is very useful and popular in many areas of our life, for example:
    • Income from bank deposit is usually defined as percent of capital, that you would earn after one year. It's so called annual rate of return.
    • Change in a value is often expressed as percentage of inital value. For example: the handbag is 20% cheaper than it was before the summer discount.
    • Concentration of one substance in another is often expressed in percentage values (percentage concentration). For example you can buy 3% solution of hydrogen peroxide to desinfect wounds. It means that in 100g of solution you'll get 3g of the active substance (i.e. hydroden peroxide).

How to use this tool

  • First of all, find the sentence in calculator, which describes your problem in the closest way. However, don't take those sentences too literally ! Those sentences describe example situations - like buying handbag under promotion. However, you can put any other product in this place. Be creative, don't waste your imagination.
  • Next, click on one of input fields in the sentence and enter your own value.
  • After you've entered the numbers in the particular sentence, the other part of a sentence will adjust automatically, displaying the correct number as a solution.
  • Remember - if you can't find a sentence describing your situation, feel free to drop us a word. We will be happy to add the missing case for you!

Ancient version of this site - links

"Calculla v1" version of this calculatorIn December 2016 the Calculla website has been republished using new technologies and all calculators have been rewritten. Old version of the Calculla is still available through this link: We left the version 1 of Calculla untouched for archvial purposes.
Direct link to the old version:

Links to external sites (leaving Calculla?)

Tags and links to this website

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