About Ratio Calculator
Ratios compare quantities and can be simplified without changing their proportions.
Simplify ratios and solve a missing proportional value. Use this page alongside your notes to check the process, then change the inputs to explore a different example.
How to use Ratio Calculator
- Review the input labels and replace the sample values with your own details.
- Check the units, options and any grading rules. The method below explains this tool’s assumptions.
- Use the action button to generate your result. Review it before copying, downloading or printing.
Method and assumptions
Simplification divides both nonnegative whole-number terms by their HCF. For A:B = C:X, cross-multiplication gives X = B × C ÷ A, provided A is not zero.
Worked example
12:18 simplifies to 2:3. For 12:18 = 4:X, X = 6.
Enter this example above, then change one input and compare the result. This helps you see which part of the method responds to the change.
Understanding your result
Read the main answer first, then review any supporting values, units or messages. An input warning means you should correct the relevant field and run the tool again.
For a useful comparison, change one input at a time and record both results. Avoid rounding intermediate values when checking calculations by hand.
Tips and common mistakes
- Keep both quantities in the same units when comparing like measurements.
- Recheck the example and input format if a result is unexpected.
- Keep a downloaded copy of work you want to reuse. Reloading the page resets your session.
Frequently asked questions
Is 0:0 a valid ratio?
It has no defined proportion and is rejected.
Do I need an account?
No. Use the tool directly in your browser. Inputs are kept in the current page session, so download useful work before leaving.
Can I save or print my result?
Use Copy result, Download text or Print at the bottom of Your Result. Flashcards and quizzes export their source content for reuse; citations export your edited text.