Fraction Arithmetic Calculator
Add, subtract, multiply and divide fractions, with the answer simplified.
Full fraction arithmetic
Doing arithmetic with fractions follows different rules for each operation, and it is easy to slip. This performs all four operations on fractions and gives the answer in simplest form, so you get the correct result without juggling the rules.
Enter your fractions and operation to calculate.
The rules, and where they trip people
Each operation works differently, which is the source of most fraction mistakes. Multiplying is the easy one — multiply the tops, multiply the bottoms. Dividing is multiplying by the flipped second fraction, the classic invert-and-multiply. Adding and subtracting are the tricky ones, because you first need a common denominator; the frequent error is adding the tops and bottoms directly, which is simply wrong. Once over a common denominator, you add or subtract the numerators only. Every answer should then be simplified to lowest terms. Fractions intimidate many people precisely because the rules differ per operation and run counter to the instinct to just combine the numbers, which is exactly why having them applied correctly, and simplified, is genuinely useful.
Fraction Arithmetic Calculator FAQ
Why can't I just add the tops and bottoms of fractions?
Because addition needs a common denominator first — adding numerators and denominators directly gives the wrong answer. Only once over a shared denominator do you add the tops.
How do you divide fractions?
Flip the second fraction and multiply — the classic invert-and-multiply rule.
Is anything uploaded?
No. The calculation happens in your browser.