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Math & Numbers / Free online tool

Fraction Calculator

Work with fractions and mixed numbers, simplify a fraction, or convert a decimal exactly.

Your inputs

First fraction
Second fraction
Up to 12 decimal places; entered digits are converted exactly.
Try a worked example

1 1/2 + 2 1/3 = 3 5/6, or 23/6.

1½+2⅓=3⅚

Calculated in your browser. Your inputs stay on this device.

Starting values are examples. First click or keyboard focus clears an example so you can enter yours. Reset restores the examples.

Your result

Enter your values to calculate.

Compare scenarios

Keep up to three results and their inputs during this visit. Reset clears the comparison.

Behind the answer

a/b + c/d = (ad + bc) / bd

How to use this calculator

Choose arithmetic, mixed numbers, simplification, or decimal conversion. Mixed numbers first become improper fractions. Results include reduced fraction, mixed-number and decimal forms, and working. A negative whole-number part applies to the entire mixed number.

  1. Enter calculation, first whole-number part, first numerator and review the remaining options.
  2. Select Calculate or change a value to update the result. Read the result label and units before copying.
  3. Use Reset to restore the worked starting values.

Formula and method

a/b + c/d = (ad + bc) / bd

Arithmetic accepts safe integer numerators and nonzero integer denominators. Mixed fractional parts are nonnegative with positive denominators. Decimal conversion preserves at most 12 entered decimal places, not an inferred repeating decimal. Big-integer mode supports up to 999 digits per integer and shows up to 24 decimal places.

Worked example

1/2 + 1/3 = 5/6.

Questions about fraction calculator

How do I add fractions with different denominators?

Multiply across to form a common denominator: a/b + c/d = (ad + bc)/(bd). For 1/2 + 1/3 this gives 5/6. Choose Mixed-number arithmetic to enter whole-number parts, or Decimal to fraction to convert a finite decimal exactly.

What assumptions should I check?

Arithmetic accepts safe integer numerators and nonzero integer denominators. Mixed fractional parts are nonnegative with positive denominators. Decimal conversion preserves at most 12 entered decimal places, not an inferred repeating decimal. Big-integer mode supports up to 999 digits per integer and shows up to 24 decimal places.

Are my inputs saved?

Calculations run in your browser. We store only tool IDs for favorites and recent tools. A calculation link contains your inputs only when you explicitly choose to copy one.