← Back to Student Tools
Proportion Calculator
Proportion Calculator
Solve proportions like
a/b = c/d
. Leave one field empty to solve for it.
a
b
=
c
d
Rounding
4 decimals
3 decimals
2 decimals
1 decimal
Whole number
If multiple blanks…
Auto (solve first blank)
Solve for a
Solve for b
Solve for c
Solve for d
Equality tolerance
Strict
Normal
Loose
Calculate
Clear
Copy result
Result: —
Check: —
Method: —
Shortcuts:
Enter
calculate ·
R
clear.
Explanation
Solves simple proportions (equivalent fractions).
For
a/b = c/d
, you can solve for any missing value by cross-multiplying.
Cross-multiply:
a×d = b×c
.
Example: if d is missing →
d = (b×c) ÷ a
.