Free Ratio Calculator Online
Use this calculator to simplify ratios, convert ratio parts to percentages, solve missing values in equivalent ratios, and divide totals in a ratio.
1) Simplify and Scale a Ratio
2) Equivalent Ratio (Find the Missing Value)
Solves: A:B = C:D. Enter three values and leave one field blank.
3) Divide an Amount in a Ratio
What is a ratio calculator?
A ratio calculator is a quick online tool that helps you compare quantities and perform common ratio math without doing every step by hand. Ratios appear in daily life all the time: recipes, budgets, map scales, finance planning, classroom problems, and construction measurements.
Instead of manually reducing numbers, converting parts to percentages, or scaling values to a new total, you can enter your values and get immediate results.
What this online ratio calculator can do
- Simplify ratios to lowest terms (for example, 12:18 becomes 2:3).
- Convert a ratio to percentages so each part is easier to interpret.
- Scale ratios to hit a specific total amount.
- Solve equivalent ratios using A:B = C:D when one value is missing.
- Divide money or quantities in a ratio for fair allocation.
How to use the calculator
Simplify a ratio
Enter Part A and Part B, then click Simplify Ratio. The tool reduces the numbers to smallest whole-number form when possible and also shows the original ratio value.
Convert ratio to percentage
Click Ratio to Percent after entering A and B. You will see what percentage each part contributes to the total.
Scale ratio to a target total
Enter A, B, and a target total, then click Scale to Total. This is useful for resizing recipes, investment allocation targets, or inventory planning.
Find a missing value in equivalent ratios
In the equivalent ratio section, fill in any three fields and leave one blank. Click Solve Missing Value to compute the unknown.
Divide an amount in a ratio
Enter a total and the ratio parts. Click Divide Total to split the total in proportion. Great for partnership payouts, shared expenses, or classroom exercises.
Real-world examples
1) Budget allocation
If you want to split your savings in a 3:2 ratio between long-term investments and emergency funds, this tool instantly shows exact dollar amounts for any total.
2) Recipe scaling
Suppose a sauce uses oil and vinegar in a 1:3 ratio, but you want exactly 400 ml total. The calculator gives the correct amounts without guesswork.
3) Team commission split
If two contributors share payment in a 5:4 ratio, dividing the final amount takes seconds and avoids rounding mistakes.
Why use an online ratio calculator instead of manual math?
- Faster calculations for homework and work tasks
- Fewer arithmetic errors
- Handles decimals and scaling cleanly
- Useful on mobile and desktop
Tips for accurate ratio results
- Use non-negative values for most practical applications.
- For equivalent ratio solving, leave exactly one input blank.
- If you are dividing a total, make sure the ratio parts are not both zero.
- Round final answers based on your use case (money, grams, percentages, etc.).
Conclusion
This ratio calculator online is designed to be simple, fast, and flexible. Whether you need ratio simplification, equivalent ratio solving, percentage conversion, or proportional distribution, the tool above gives dependable results in one place.