Example 1
- Operation: add
- 1/2 and 1/3
5/6
What is 1/2 plus 1/3? 5/6, because 3/6 plus 2/6.
Fraction Calculator
The calculator adds, subtracts, multiplies, and divides two fractions, then reduces the result. 1/2 plus 1/3 is 5/6. 3/4 times 2/5 is 3/10.
This is not the fractional part of a number and not a fractional power. The leftover after the integer is on the fractional part page.
Result
Enter the fractions. The reduced result will appear here.
How it works
The calculator uses whole-number numerators and denominators. For add and subtract the common denominator is the product of both denominators. 1/2 plus 1/3 is 3/6 plus 2/6, which is 5/6.
For multiply the numerators multiply and the denominators multiply. 3/4 times 2/5 is 6/20, and after reducing by 2 that is 3/10.
For divide you multiply the first fraction by the reciprocal of the second. (1/2) ÷ (1/4) is (1/2) × (4/1), which is 2.
Reduce divides the numerator and denominator by the greatest common divisor. 2/4 becomes 1/2. If the reduced denominator is 1, the main result is a whole number.
A denominator of 0 is not accepted. A minus in the denominator moves to the numerator, so 1/−2 and −1/2 give the same result.
This is not the fractional part of 3.25 and not a fractional power. A percent of a number is on a separate page.
Formula
a/b + c/d = (a×d + c×b) / (b×d), then reduce by the GCD
Multiply: (a×c)/(b×d). Divide: (a×d)/(b×c). Reduce: divide numerator and denominator by the greatest common divisor.
How to use
- Choose add, subtract, multiply, divide, or reduce one fraction.
- Enter the numerator and denominator. For two fractions fill both pairs, for example 1/2 and 1/3.
- Choose Calculate. The main result is already reduced. Beside it you see the decimal and the form before reducing.
- Keep the denominator different from zero. To reduce 2/4 the first pair is enough.
5/6 from 1/2 plus 1/3
The common denominator 6 gives 3/6 plus 2/6. The sum 5/6 does not reduce further.
- GCD
- Greatest common divisor. For 6 and 20 it is 2, so 6/20 becomes 3/10.
- 5/6
- 1/2 + 1/3 after bringing both to denominator 6.
- 3/10
- 3/4 × 2/5. First 6/20, then reduce by 2.
Examples
Example 2
- Operation: multiply
- 3/4 and 2/5
3/10
What is 3/4 times 2/5? 3/10 after reducing 6/20 by 2.
Example 3
- Operation: reduce one fraction
- 2/4
1/2
What does 2/4 reduce to? 1/2. The greatest common divisor is 2.
Related calculators
Frequently asked questions
What is 1/2 plus 1/3?
5/6. The common denominator is 6: 3/6 plus 2/6. As a decimal that is 0.8333.
What is 3/4 times 2/5?
3/10. First 6/20, then reduce by 2. As a decimal that is 0.3.
What does 2/4 reduce to?
1/2. The greatest common divisor is 2.
Can the denominator be zero?
No. A fraction with denominator 0 is not a number. The calculator does not accept that input.
Do the numerator and denominator have to be whole numbers?
Yes. The calculator does not accept 1.5. Write 3/2 instead of one and a half.
How is this different from the fractional part?
The fractional part is what remains after subtracting the integer part, for example 0.25 from 3.25. Here you compute two fractions.
How do you divide fractions?
You multiply the first fraction by the reciprocal of the second. (1/2) ÷ (1/4) is (1/2) × (4/1), which is 2.
What about a minus in the denominator?
The sign moves to the numerator. −1/2 and 1/−2 give the same result −1/2.
Does 4/2 stay a fraction?
The main result is 2, because the reduced denominator is 1. The raw 4/2 sits beside it.
Is this a fractional power?
No. A fractional power is on a separate page. Here you add, subtract, multiply, divide, and reduce fractions.
Sources
Reducing a fraction uses the greatest common divisor. Denominator 0 is not a number.
Page updated in 2026.