Fraction Calculator

Add, subtract, multiply, or divide two fractions and automatically reduce the exact result.

Fraction arithmetic calculator
Choose an operation and enter integer numerators and nonzero denominators.

First fraction

Second fraction

About the fraction calculator

A fraction represents a numerator divided by a nonzero denominator. The numerator counts how many parts are present, while the denominator describes how many equal parts make one whole. This calculator performs the four basic arithmetic operations on two fractions and reduces the result to lowest terms. It uses integer arithmetic throughout, so familiar fraction inputs produce exact rational answers rather than rounded decimal approximations. Addition and subtraction require a common denominator. For a divided by b plus c divided by d, cross multiplication produces the numerator ad + bc over the denominator bd. Subtraction uses ad - bc over bd. The calculator may use a product denominator even when a smaller common denominator exists, because the final simplification removes every common factor and yields the same reduced answer. For example, one half plus one third becomes three sixths plus two sixths, which equals five sixths. Multiplication is direct: multiply the numerators together and multiply the denominators together. Two thirds times three fourths initially gives six twelfths, then reduction gives one half. Division uses the reciprocal of the second fraction. Dividing a divided by b by c divided by d is equivalent to multiplying a divided by b by d divided by c. The second numerator therefore cannot be zero during division because its reciprocal would have a zero denominator. Reduction uses the greatest common divisor of the result's numerator and denominator. Dividing both by that factor preserves the fraction's value while removing shared factors. A negative sign is normalized onto the numerator so the denominator remains positive. If the reduced denominator equals one, the calculator displays the result as an integer. Fractions are used in recipes, measurements, probability, ratios, geometry, finance, and algebra. Keeping answers as reduced fractions avoids the precision loss that can occur when repeating decimals are rounded. To check an answer, estimate each input as a decimal and confirm that the result has a reasonable size and sign. Also remember that denominators can never be zero, and division by a fraction equal to zero is undefined. With valid integer inputs, the calculator provides a concise exact answer suitable for homework checks and everyday arithmetic.

Fraction arithmetic examples

ExpressionReduced resultMethod
1/2 + 1/35/6Use a common denominator of six.
3/4 - 1/67/12Subtract equivalent fractions over twelve.
2/3 × 3/41/2Multiply, then reduce six twelfths.
5/8 ÷ 2/315/16Multiply five eighths by the reciprocal three halves.

How to use the fraction calculator

  1. Choose Addition, Subtraction, Multiplication, or Division.
  2. Enter the numerator and nonzero denominator of the first fraction.
  3. Enter the numerator and nonzero denominator of the second fraction.
  4. Select Calculate Fractions to see the exact reduced result.

Fraction calculator FAQ

How do I add fractions with different denominators?

Create equivalent fractions with a common denominator, then add their numerators. The calculator uses cross multiplication and reduces the resulting fraction automatically.

How are fractions multiplied?

Multiply the two numerators and multiply the two denominators. Reduce the resulting numerator and denominator by any shared factors.

How do I divide by a fraction?

Flip the second fraction to form its reciprocal, then multiply. The second fraction cannot equal zero because zero has no reciprocal.

What does lowest terms mean?

A fraction is in lowest terms when its numerator and denominator share no factor greater than one. It has the same value as the unreduced fraction but is easier to interpret.

Can a denominator be negative?

Yes, the value is valid as long as the denominator is not zero. The calculator moves the negative sign to the numerator when it formats the reduced result.

Why are only integer fraction parts accepted?

Standard numerator-over-denominator notation uses integers to represent an exact rational number. Decimal quantities can first be converted to equivalent fractions before using this calculator.