Free Online Fraction Calculator

Fractions can sometimes be a little tricky - use our free online fraction calculator to quickly add, subtract, multiply, or divide any two fractions.

Note: Requires the free Adobe Flasher Player 10.

Directions: How to use the calculator

  1. Enter the first fraction by entering a numerator and denominator.

  2. Choose the operation you wish to perform (add, subtract, multiply, divide) by clicking on the appropriate radio button.

  3. Enter the second fraction by entering a numerator and denominator.

  4. Click Calculate!

  5. To calculate another fraction, click clear all and then repeat the above steps.

As always, only use this fraction calculator if you know how to do the operations by hand first!

If you need some extra help, visit our free fraction help page, which shows all the rules of fractions, from operations, to conversions, and more.

You may also like other free online calculators.


How the Free Online Fraction Calculator Works

The calculator first identifies the values that you input for the numerator and denominator of each fraction. It then assigns them to the following variables: top1, bottom1, top2, and bottom2. Next, it determines which operation you would like to perform by checking the four radio buttons. Depending on which radio button you selected, it performs one of four calculations:


Additon: (top1*bottom2 + bottom1*top2) / (bottom1*bottom2)

Subtraction: (top1*bottom2 - bottom1*top2) / (bottom1*bottom2)

Multiplication: (top1*top2) / (bottom1*bottom2)

Division: (top1*bottom2) / (bottom1*top2)

After performing one of the above calculations, the calculate now has a new top and a new bottom, called topR and bottomR, where R stands for "Result." Before we display the answer, we need to complete the last step: reduce the fraction.

Because the calculator performed the operations with the original values, the fractions can be quite large - so it runs a "loop" to determine the simplest form of the fraction. Once it finds the simplest form, it displays the simplified numerator and the simplified denominator. Finally, it puts a red circle around the answer to show you it is complete!

Additional information

Now that you've used our free online fraction calculator to easily perform fraction operations, you may want to try some of our other free online math calculators.

Fraction to decimal calculator

Decimal to fraction calculator

Percentage calculator

Percentage change calculator





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