Fraction & ratio calculator
Add, subtract, multiply and divide fractions, mixed numbers and decimals exactly, with step-by-step working; simplify and convert fractions, decimals and percentages; simplify ratios, split a total and solve proportions. Fully offline.
Open Fraction & ratio calculator →What is the fraction & ratio calculator?
A free fraction calculator that adds, subtracts, multiplies and divides fractions, mixed numbers, whole numbers and decimals using exact whole-number arithmetic, so there is never a rounding error. Every answer is shown as a simplified fraction, a mixed number, a decimal with any repeating digits marked, and a percentage, with short step-by-step working. It also converts between fractions, decimals and percentages, simplifies ratios, splits a total in a ratio and solves proportions — all in your browser and fully offline.
How to use Fraction & ratio calculator
- Pick a tab — Fractions does arithmetic on two numbers, Simplify & convert turns one value into every other form, and Ratios & proportion holds the three ratio tools.
- Type your numbers — Enter whole numbers (5), fractions (3/4), mixed numbers (1 3/4), decimals (0.125) or repeating decimals with the repeating digits in brackets (0.(3)). The result updates as you type.
- Choose an operation — On the Fractions tab, pick +, −, × or ÷. The working shows the lowest common denominator, the multiplication and the final division by the greatest common divisor.
- Copy the answer — Use the copy button at the top of the tool to copy the current tab's result as plain text. Your inputs are saved on your device for next time.
Frequently asked questions
Why is this more accurate than an ordinary calculator?
It never converts to floating-point numbers. Every value is held as a numerator and denominator of whole numbers of any size, so 1/3 stays exactly 1/3 and very large numbers keep every digit.
How do I enter a repeating decimal?
Put the repeating digits in brackets: 0.(3) is 0.333…, 0.1(6) is 0.1666… and 0.(142857) is 1/7. In results the repeating block is marked with a line over it.
Can a ratio contain decimals?
Yes. Parts such as 1.5:2.25 are multiplied up to whole numbers first, then divided by their greatest common divisor, giving 2:3.
How does the proportion solver work?
Fill in three of the four boxes in a : b = c : d and leave one empty. It cross-multiplies (a × d = b × c) and solves for the missing term. If all four are filled it tells you whether the proportion holds.
What happens if I divide by zero?
No result is shown; a short message under the inputs explains the problem instead.
Tips
- Type a percentage such as 12.5% on the Simplify & convert tab to get it as a fraction (1/8).
- Negative numbers work everywhere in the Fractions tab — for example -2/3 − 1/6 = -5/6.
- When a split does not divide evenly, the exact shares are shown as fractions beneath the decimals.