PERCENTAGES · POWERS · ROOTS
Percentage, power, and root calculator
Calculate a percentage of a value, increase or decrease an amount, compare values, or find a power or nth root. The calculator accepts a decimal point or comma.
Full mode adds reverse percentages, compound interest with compounding, and successive percentage changes. Calculations run in your browser, with an adjustable display precision and formula details.
Calculate a percentage of a number, a value change, compound interest, a power, or an integer root. The calculator accepts either a decimal point or comma and supports Russian and English.
Use the calculator for common and study tasks: find a percentage of a value, express a part as a percentage, increase or decrease an amount, compare two values, or recover an original amount. Full mode also handles compound interest and a sequence of percentage changes.
A separate tab calculates powers and nth roots. Calculations run in the browser, displayed precision is adjustable, and each result includes its formula for review.
Choose a calculation
RESULT
Calculation result
Enter values and select “Calculate.”
Common examples
Formulas and precision
- Percentage of a value: value × percentage ÷ 100. Percentage change: (new − original) ÷ |original| × 100%.
- Compound interest: principal × (1 + rate ÷ frequency)^(frequency × term). Successive percentages are applied one after another to the running result.
- A power is calculated as base^exponent; an nth root is its inverse. Negative values have real roots only at odd degrees.
- Numbers use JavaScript double precision; significant digits affect display only. Final decimal places may reflect normal binary floating-point rounding.
Frequently asked questions
How do I find a percentage of a number?
Open the Percentages tab, choose “What is P% of a number?”, and enter the percentage and value. The calculator uses value × percentage ÷ 100. For example, 15% of 240 is 36.
How do I increase or decrease a value by a percentage?
Choose Increase or Decrease, then enter the original value and percentage. Decreasing 80 by 20%, for example, gives 64; the percentage is applied to the original value.
How do I express a part as a percentage of a whole?
Choose the part-to-whole calculation and enter both values. The result is part divided by whole, multiplied by 100. The whole cannot be zero.
How is percentage change calculated?
In Full mode, choose Percentage change and enter the original and new values. The formula divides the difference by the absolute original value; percentage change from zero is undefined.
Can I find the original value from a known percentage?
Yes. In Full mode, select the reverse percentage calculation, then enter the known amount and its percentage. If 30 is 15% of a value, the calculator returns 200.
How does compound interest work in this calculator?
Enter the principal, annual percentage rate, term in years, and compounding frequency. The calculation uses A = P × (1 + r/n)^(n×t), where n is the number of compounding periods per year.
Which compounding frequencies can I use?
Enter 1 to 365 compounding periods per year, such as 1 for annual, 4 for quarterly, or 12 for monthly compounding. The rate is entered as an annual percentage.
How do I apply several percentage changes in sequence?
In Full mode, enter a starting value and place each percentage change on a separate line. Positive values increase the current amount and negative values decrease it; each change applies to the updated result.
Can I raise a number to a fractional power?
Yes, when the result is a real number. A negative base accepts integer exponents; fractional powers of negative values are generally not real-valued.
How do I calculate an nth root?
Open the Powers and roots tab, choose the root operation, and enter the radicand and an integer degree from 1 to 10,000. For example, the fourth root of 81 is 3.
Can I take a root of a negative number?
A real root of a negative value exists for odd degrees: the cube root of −8 is −2. An even root of a negative value is not a real number.
How should I enter decimal numbers?
Use either a dot or a comma as the decimal separator, such as 2.5 or 2,5. Digit-grouping spaces are not accepted, avoiding ambiguous input.
What does the significant-digits setting change?
It changes only how the result is displayed. Calculations use JavaScript double-precision numbers, so the setting does not add arithmetic precision or remove normal binary rounding.
What is different in Simple mode?
Simple mode keeps common percentage operations and standard display precision. Full mode also provides percentage change, reverse percentage, compound interest, successive changes, and precision choices.
Are my numbers sent to a server?
No. Percentages, powers, and roots are calculated by JavaScript in your browser. Use the button beside the result to copy it.