Fraction Calculator
Add, subtract, multiply, or divide fractions and see simplified and decimal results.
Inputs
Result
Enter values on the left and select Calculate to see the result here.
What the Fraction Calculator does
- Performs addition, subtraction, multiplication, or division on two fractions entered in a/b form.
- Shows the raw calculated fraction, a simplified fraction, and a rounded decimal equivalent based on the current implementation.
- Can help with maths homework checks, recipes, proportions, scaling, and everyday fraction work when inputs are entered carefully.
How to use the Fraction Calculator
- Enter each fraction in numerator/denominator form, such as 3/4 or -5/8. Whole numbers can be entered as 5/1.
- Choose add, subtract, multiply, or divide, then click Calculate.
- Check signs, denominators, operation choice, simplification, and any rounded decimal result before relying on the answer.
Formula / methodology used
- For addition and subtraction, the calculator cross-multiplies to form a common denominator: a/b ± c/d = (a×d ± c×b)/(b×d).
- For multiplication, it multiplies numerators and denominators: a/b × c/d = (a×c)/(b×d).
- For division, it multiplies by the reciprocal: a/b ÷ c/d = (a×d)/(b×c), and rejects division by a zero numerator in the second fraction because that creates a zero denominator.
- It simplifies the result by dividing the numerator and denominator by their greatest common divisor, normalizes a negative denominator to the numerator, and rounds the decimal equivalent to 6 decimal places.
Example calculation
Add 3/4 and 1/6.
- Use common denominator 4×6 = 24
- Cross-multiply the numerator: 3×6 + 1×4 = 18 + 4 = 22
- Raw result = 22/24
- Simplify by gcd(22, 24) = 2, so 22/24 = 11/12
- Decimal equivalent = 11 ÷ 12 = 0.916666..., rounded to 0.916667
Result: The calculator would show raw result 22/24, simplified fraction 11/12, and decimal 0.916667.
Common mistakes and limitations
- The calculator expects two fractions in a/b format and does not directly parse mixed-number notation such as 1 1/2.
- Decimals are rounded to 6 decimal places, so repeating decimals are approximate.
- Incorrect signs, swapped numerators and denominators, or a zero denominator will produce incorrect or invalid results.
Important note
This fraction calculator is a general maths helper based on your inputs. Do not use it as the only check for exams, engineering, medical dosing, construction, legal, financial, or other high-stakes calculations.
Fraction Calculator FAQs
What input format is supported?
Use a/b with a non-zero denominator, such as 5/8 or -3/10. Mixed numbers are not parsed directly; convert them first, such as 1 1/2 to 3/2.
What happens if I divide by zero?
A fraction with denominator 0 is invalid. Dividing by 0/anything is also invalid because the reciprocal would create a zero denominator.
Can I use this as my only check for exams or professional calculations?
No. It is a helpful arithmetic aid, but you should independently check exam work and use appropriate professional methods for engineering, medical dosing, construction, legal, or financial calculations.