Percentage formulas

You can also use negative values in formulas. If you use only positive values, you can of course use A instead of |A|.

A% of number B = C

C = A 100 × B
A = C B × 100    ( B 0 )
B = C A × 100    ( A 0 )
Example: 15% of 200 = 30
30 = 15 100 × 200
15 = 30 200 × 100
200 = 30 15 × 100

Percentage calculator

Original price A is discounted/raised by B%. The resulting sales price is C

Original price of product: A
Price has been discounted B%
Final sales price is C

C = A - ( | A | × B 100 )
B = A - C | A | × 100    ( A 0 )
A = C 1 - B 100    ( B 100 )
Example: Original price 60, 20% discount = Sales price 48.
48 = 60 - ( 60 × 20 100 )
20 = 60 - 48 60 × 100   
60 = 48 1 - 20 100

Original price of product: A
Price has been raised B%
Final sales price is C

C = A + ( | A | × B 100 )
B = C - A | A | × 100    ( A 0 )
A = C 1 + B 100    ( B -100 )

Percentage calculator: Original price A is discounted/raised by B%. The resulting sales price is C

How much is A% of B?

X = A 100 × B

Percentage calculator: How much is A% of B?

How many % is A of B?

X % = A B × 100 %    ( B 0 )

Percentage calculator: How many % is A of B?

How many percentages bigger or smaller is the second number?

First number is A. Second number is B.
What is the change (increase or decrease) from first number to second number?
= How many percentages bigger or smaller is the second number?

X % = B - A | A | × 100 %    ( A 0 )

Percentage calculator: How many percentages bigger or smaller is the second number?

See also: Alternatives to calculating change

Number A is increased by B%

X = A + ( B 100 × | A | )

Percentage calculator: Number A is increased by B%

Number A is decreased by B%

X = A - ( B 100 × | A | )

Percentage calculator: Number A is decreased by B%

Alternatives to calculating change

Percentage change

X % = B - A | A | × 100 %    ( A 0 )

Percentage difference

X % = | B - A | [ A + B 2 ] × 100 %    ( A > 0 , B > 0 )

Log difference

X = ln ( B ) - ln ( A )    ( A > 0 , B > 0 )

or

X = ln ( B A )    ( A > 0 , B > 0 )

Percentage calculator: Alternatives to calculating change

Articles

How to write a percent: language and country-specific tables
Percents are written differently in different parts of the world and in different languages. The writing style can be, for example, '75.6%', '75,6%', '75.6 %', '75,6 %' or even '%75.6'. See the writing rules in the tables that list almost all countries and languages in the world.

Decimal separator and thousand separator
In English-speaking countries, a dot is used as a decimal separator. The European custom is to use a comma. A dot, comma, or space are used as thousand separators in different parts of the world. See the table for the practices of each country.

Percent sign and space: 50% is English, 50 % is European
There is no space between the percent sign (%) and the number in English language. In other European languages there is. However, it is common to leave the space out.

Percentage calculations without a calculator
Percentage calculations become much easier when we understand that they are multiplication calculations. You can put the numbers to be calculated in a different order. You can also separate the tens and hundreds into their own numbers.

Negative percent
A percentage calculation can easily result in a negative percentage instead of a positive percentage. You can also calculate a percentage from a negative number. The calculation gets a bit strange when you calculate the percentage change using a negative number, but that's not impossible either.

Percentage and percentage point
A percentage means a hundredth and they are used to measure a share of something. The percentage point, on the other hand, is used when comparing percentages to each other or when referring to percentages of certain percentages.