Convert a value between decimal and percent notation in either direction.
How it works
A percent is simply a decimal multiplied by 100: percent = decimal × 100, and the reverse divides by 100. 0.45 is 45%; 1.25 is 125%.
What this does not include
This is a pure notation conversion. For percentage calculations like “what is 15% of 200” or “percentage change from A to B,” see this site’s main percentage calculator instead.
How to use this calculator
- Enter a value as a decimal or as a percent.
- The other field updates automatically.
Why can a percent exceed 100%?
Because the underlying decimal can exceed 1 — 1.25 represents “one and a quarter times” something, which is a perfectly normal value, just expressed as 125%.
Can a decimal or percent be negative?
Yes — a negative decimal converts to a negative percent the same way, representing a decrease rather than an increase.
Why do percentages use the % symbol instead of just writing the decimal?
Percent notation makes proportions easier to compare at a glance — most people find “45% off” more immediately readable than “a 0.45 discount factor.”
