When to use this calculator
Scale a directly proportional quantity from one known input-output pair. Assumes output is proportional to input with no fixed offset.
Explore the algebra & number calculators for other questions in this topic. For a related calculation, use the Distance Between Points Calculator: Find the straight-line distance between two coordinates in a plane.
PUTTING IT INTO PRACTICE
Direct Proportion: a worked example
The values below are an illustrative example, not a recommendation. Replace them with measurements or assumptions that match your question.
| Input | Example value |
|---|---|
| Known input | 4 |
| Known output | 12 |
| New input | 10 |
| Result | 30 |
- Check the input labels and enter the example values above.
- Apply the relationship: New output = known output × new input/known input.
- The result is 30 , rounded for display.
How to interpret your result
Assumes output is proportional to input with no fixed offset.
Identify whether the question asks for one term, a total or a count of possible selections. Sequences use a fixed difference or ratio. In counting problems, order and replacement determine the correct model.
Frequently asked questions
Do combinations and permutations count the same thing?
No. Combinations ignore the order of selection; permutations count different orders separately.
When is the direct proportion calculator useful?
Scale a directly proportional quantity from one known input-output pair. Assumes output is proportional to input with no fixed offset.
How do I use the direct proportion calculator?
Enter known input, known output, new input. The result updates automatically. Use the units shown beside each input; the example values illustrate the method.
Which formula does this calculator use?
New output = known output × new input/known input.
What should I check before using the result?
Assumes output is proportional to input with no fixed offset.
How are results rounded?
Scalar numbers display up to six decimal places, with scientific notation for very large or small values. Text, fraction, date and schedule outputs use the format described on the tool. Intermediate calculations use JavaScript floating-point arithmetic. Keep sensible precision for your measurements.
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