Calculator directory3 tools
Proportion Math Calculators
Work with proportional relationships, variation equations, and percent conversions using exact fractions instead of rounded decimals.
These proportion math calculators cover the school and everyday side of
proportions: deciding whether quantities are proportional, building the
equation that connects them, and moving between percents, fractions,
decimals, and ratios. Every tool works in exact rational arithmetic, so
1/3 stays 1/3 until the final decimal is displayed.
Choose the Right Proportion Math Calculator
| Question | Use this tool |
|---|---|
| Is this table of x and y values proportional, and what is the constant k? | Proportional Relationship Calculator |
| Two quantities vary directly or inversely—what is the missing value? | Direct and Inverse Proportion Calculator |
| How do I convert a percent to a fraction, decimal, or ratio, or back? | Percent Proportion Calculator |
If the task is solving one proportion equation a / b = c / d for a single
missing value, use the proportion calculator on the home page; it is the
site’s flagship solver. For ratio simplification, comparison, and dividing a
total in a given ratio, use the
ratio and proportion calculator.
Tables, Graphs, and Equations
A proportional relationship can be recognized three ways: every y / x ratio
in a table is the same, the graph is a straight line through the origin, and
the equation has the form y = kx. The tools in this section move between
those views—checking the table, reporting the constant of proportionality
k, and writing the equation—so the same relationship can be used in
whichever form a problem requires.
Exact Fractions Instead of Rounded Decimals
Proportion homework fails most often at premature rounding. These calculators parse integers, decimals, fractions, and mixed numbers exactly, keep every intermediate step as a rational number, and only convert to a decimal at the end, flagging the result as exact or approximate. That makes the shown work safe to copy into an answer that requires a fraction.
Each calculator explains its method and limits on its own page. None of them collect the numbers you enter; all arithmetic runs in your browser.
Proportional Relationship Calculator
Test whether a table of x and y values is proportional, find the constant of proportionality k, and get the equation y = kx with every ratio shown.
Direct and Inverse Proportion Calculator
Solve direct proportion y = kx or inverse proportion y = k/x from one known pair. Get the constant k, the equation, the missing value, and a verification step.
Percent Proportion Calculator
Convert a percent to a simplified fraction, exact decimal, and part-to-whole ratio, or turn any fraction, decimal, or ratio back into a percent, step by step.