Four percentage questions in one tool: what X percent of a value is, what share one number is of another, an increase or decrease in percent, and the percentage change between two values.
Results are rounded to two decimals. One comma or dot is the decimal separator (12,5 or 12.5); thousands separators work in pairs, as in 1.234,56. The percentage change in the fourth mode is (B minus A) divided by the absolute value of A, so 100 to 80 is -20 percent.
This percentage calculator answers four questions, and the buttons above the fields decide which one is calculated. In the first mode you enter a percentage and a base value and get the amount it represents, for example 25 percent of 200. The second mode turns that around: two numbers go in, the share of the first in the second comes out, so 1 of 3 gives 33.33 percent. The third mode applies a change: type the change in percent, negative for a reduction, and you get the new value and the difference. The fourth mode reports the percentage change between two values, so 100 to 80 is -20 percent. Labels always show which number goes in which field, results round to two decimals, and 12,5 as well as 12.5 are accepted. Dividing by zero is reported as an error instead of an unlimited number. The tool does arithmetic only, draws no charts and stores nothing: it runs in your browser.