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Proportion Calculator
Solve a proportion a/b = c/x for the missing value.
⚖️ Free Online Tool
⚡ Instant Results
📊 Clear Comparison
🔒 100% Free Tool
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Compare Your Options And Get Clear Answers
Solve a proportion a/b = c/x for the missing value.
Proportion Estimator
Enter your numbers below for an instant estimate.
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💡 Tip: If a/b = c/x then x = b x c / a.
How It Works
Key concepts behind this calculator
1
Enter Values
Fill in each field with your own numbers.
2
Calculate
Results update as you change the inputs.
3
Review
Read the breakdown and the explanation.
4
Adjust
Change values to compare scenarios.
Quick Reference Guide
Proportion Quick Guide
Typical values for reference.
| Proportion | Solve | Answer | Check |
|---|---|---|---|
| 3/4 = 9/x | x = 12 | 12 | Yes |
| 2/5 = 6/x | x = 15 | 15 | Yes |
| 1/2 = 7/x | x = 14 | 14 | Yes |
| 5/8 = 15/x | x = 24 | 24 | Yes |
| Rule of Thumb | Check inputs | Use as a guide | Round sensibly |
Common Questions
Proportion Calculator FAQ
Answers to common questions about this calculator.
Cross multiply, then divide by the remaining number.
It gives a quick estimate of proportion from the values you enter.
No. It is a planning estimate, so check important figures with a professional or official source.
Yes. Edit any field and the result updates when you calculate.