Percent Calculator for Calculating Missing Percentage Variable Given the Other Two

Percent Calculator Sign

This free online percentage calculator can calculate percentages in the following three ways.

1. What percentage is one number of another number.

2. What unknown number is a given percentage of another number.

3. What unknown number is a given number a given percentage of.

Plus, unlike other online percentage calculators, this percent calculator allows you to choose the decimal rounding, explains how it arrived at the given result and shows a visual representation of the result in a pie chart.

Other Percent-Related Calculators

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Percent Calculator

Calculate missing percent variable given any two of the three variables.

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Selected Data Record:

A Data Record is a set of calculator entries that are stored in your web browser's Local Storage. If a Data Record is currently selected in the "Data" tab, this line will list the name you gave to that data record. If no data record is selected, or you have no entries stored for this calculator, the line will display "None".

DataData recordData recordSelected data record: None
Round to:Decimal places:Decimal places to round to:Number of decimal places to round result to:

Number of decimal places to round result to:

Select how many decimal places you would like the result rounded to. Note that the percent calculator will always give the raw result in the field provided, and then use the rounded version for the result explanation and the pie chart.

Enter any 2 of 3 variables:

Enter any two of the three variables:

Fill in two of the three fields depending on which solution you are looking for (using digits 0-9 and decimal points only). The missing term will be displayed by the percent calculator after clicking the Calculate Missing VariableCalculate Missing VariableCalculate Missing Percent VariableCalculate Missing Percent Variable button.

The number 
#
is 
%
of the number 
#
Raw result (no rounding):

Raw result:

This is the un-rounded version of the calculated result.

If you would like to save the current entries to the secure online database, tap or click on the Data tab, select "New Data Record", give the data record a name, then tap or click the Save button. To save changes to previously saved entries, simply tap the Save button. Please select and "Clear" any data records you no longer need.

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Help and Tools

Learn

How to calculate percentages.

Besides using the percent calculator on this site, there are basically two different ways to calculate percentages:

  1. Using a shortcut method.
  2. Using a proportion method.

There are also two general uses for percent calculations:

  1. Calculating a percentage from numbers.
  2. Calculating numbers from a percentage.

To explain how to calculate percentages, I will cover both methods for each use. But first, let's make sure you aware of the conversion concepts you need to know to solve for unknown percentage variables.

Percent Conversions

The first thing you need to be aware of when calculating percentages is that a percentage (p) can be rewritten as the fraction p/100.

In other words, 25% can be rewritten as 25/100. And since 25 ÷ 100 is equal to .25, you can see that a percentage can either be converted to a fraction or a decimal. The actual conversion you will need to make will depend on whether you are using the shortcut method or the proportion method.

Number Conversions

The second thing you need to be aware of when calculating percentages, is that the numbers needed to calculate percentages (n and d) can also be rewritten as the fraction n/d, where n is a relationship or ratio to d.

For example, if you are trying to find out what percentage 5 is of the number 20, this can be expressed as 5/20. And since 5 ÷ 20 = .25, you can see that the numbers themselves can be expressed as either a fraction or a decimal. Again, the actual conversion you will need to make depends on the method you use to solve for the unknown variable.

Keeping those conversion concepts in mind, let's take a look at each method to show you how to calculate percentages from a number, and then how to calculate an unknown number from a number and a percentage.

How to Calculate a Percentage from Two Numbers

To find what percentage a first number is of a second number, the shortcut method is to simply divide the first number (numerator) by the second number (denominator). This will yield a decimal number, which can then be converted into a percentage.

To convert a decimal into a percentage, you can either multiply the decimal by 100 or simply move the decimal point two places to the right.

The following is an example of how you would calculate what percent 45 is of 180 using the shortcut method:

Shortcut Method to Solve for Percentage

p=45
180

p = .25

Convert decimal to percent:

p = .25 * 100

p = 25%

Or, you can formulate the problem into a proportion and then solve for the missing percentage. Here is how you would solve for the above example using the proportion method:

Formulate a Proportion and Solve for Percentage

45=p
180100

Cross multiply:

45 * 100 = 180 * p

4500 = 180p

Divide both sides by 180

4500=180p
180180

25 = p

25/100 = .25 or 25%

How to Calculate a Number from a Percentage and a Number

If you know the percentage and one of the needed numbers, you can find the unknown number using either the shortcut method or the proportion method. Since n/d (45/180 in our example) represents the two numbers needed to find a percentage, I'll refer to n as the numerator and d as the denominator.

Now, since the formula to find a number from a percentage and a number depends on whether or not you are trying to find the first number (n or numerator) or the second number (d or denominator), I'll explain each formula separately.

How to Calculate the Numerator Given the Percentage and the Denominator

If you are trying to find the first number (numerator), the shortcut method is to convert the percentage into a decimal and then multiply that decimal by the second number (denominator).

The following is an example of how you would calculate what number (n) is 25% of 180 using the shortcut method:

Shortcut Method to Solve for Numerator

n=25%
180

Convert percent to decimal:

25% = .25

Multiply decimal by denominator:

n = .25 * 180:

n = 45

Or, you can formulate a proportion and use cross multiplication to solve for the numerator. Here is how you would solve for the numerator in the above example using the proportion method:

Formulate a Proportion and Solve for Numerator

n=25
180100

Cross multiply:

n * 100 = 180 * 25

100n = 4500

Divide both sides by 100

100n=4500
100100

n = 45

How to Calculate the Denominator Given the Percentage and the Numerator

If you are trying to find the second number (denominator), you simply divide the first number by the decimal equivalent of the percentage.

The following is an example of how you would calculate what number (d) 45 is 25% of, using the shortcut method:

Shortcut Method to Solve for Denominator

45=25%
d

Convert percent to decimal:

25% = .25

Divide the numerator by the decimal:

d = 45 ÷ .25

d = 180

Or, you can formulate a proportion and use cross multiplication to solve for the denominator. Here is how you would solve for the denominator in the above example using the proportion method:

Formulate a Proportion and Solve for Denominator

45=25
d100

Cross multiply:

45 * 100 = d * 25

4500 = 25d

Divide both sides by 25

4500=25d
2525

180 = d

Finally, if we combine all three findings using the same example, we end up with the following statement:

The number 45 is 25% of the number 180

- or -

The number n is p% of the number d

The above explains why I set up the percent calculator the way I did. You can enter any two of the above-underlined variables, and the calculator will find the third variable.

Adjust Calculator Width:

Move the slider to left and right to adjust the calculator width. Note that the Help and Tools panel will be hidden when the calculator is too wide to fit both on the screen. Moving the slider to the left will bring the instructions and tools panel back into view.

Also note that some calculators will reformat to accommodate the screen size as you make the calculator wider or narrower. If the calculator is narrow, columns of entry rows will be converted to a vertical entry form, whereas a wider calculator will display columns of entry rows, and the entry fields will be smaller in size ... since they will not need to be "thumb friendly".

Show/Hide Popup Keypads:

Select Show or Hide to show or hide the popup keypad icons located next to numeric entry fields. These are generally only needed for mobile devices that don't have decimal points in their numeric keypads. So if you are on a desktop, you may find the calculator to be more user-friendly and less cluttered without them.

Stick/Unstick Tools:

Select Stick or Unstick to stick or unstick the help and tools panel. Selecting "Stick" will keep the panel in view while scrolling the calculator vertically. If you find that annoying, select "Unstick" to keep the panel in a stationary position.

If the tools panel becomes "Unstuck" on its own, try clicking "Unstick" and then "Stick" to re-stick the panel.