Percent Calculator
Enter the values the percent form asks for and the result is computed here, in the page, with no sign-up and no upload. Change one field at a time to see how sensitive the percent figure is to that assumption.
Calculate Percentage of a Number
Calculate Percentage Increase/Decrease
Calculate Percentage Difference
Use the scientific calculator with steps
What this percent calculator does
Enter a percentage and a base value to calculate the percentage amount. Use the same page for a quick percentage change check when comparing an original value with a new value. Keep the units consistent: dollars with dollars, points with points, and measurements with measurements.
Percentage formulas
Percentage of a value = percent divided by 100 multiplied by the base value. Percentage change = new value minus original value, divided by the original value, multiplied by 100. Percentage difference uses the average of the two values when that comparison is the intended definition.
Worked example
15 percent of 200 is 30. Adding that amount to 200 gives 230, while subtracting it gives 170. Check whether the question asks for a percentage of a value or a percentage change before choosing the operation.
Frequently Asked Questions about Percent Calculator
How do I sanity-check the percent result?
Rerun the calculator with a known example and compare it against the figure you expect; then swap back to your own numbers.
Which percent inputs change the outcome most?
Adjust one field at a time. The figure that shifts the result hardest is the assumption worth double-checking before you rely on it.
Is 15 percent the same as 0.15?
For calculation, 15 percent is represented as 0.15.
Why can a percentage change be negative?
A new value below the original produces a negative change, which represents a decrease.
Does the tool require an account?
No. It runs in the browser without signup.