Percentage Calculator
Solve everyday percentage problems instantly. Find a percent of a number, compare two values, apply an increase or decrease, reverse a finished percentage change, and understand each answer with a clear formula.
Recent calculations
How to use this percentage calculator
Choose the calculation type that matches your question, enter the values, and the answer updates immediately. The formula panel shows how the result was calculated, while the metric cards convert the answer into useful related values such as decimals, multipliers, remainder, or change direction.
Common percentage questions
- Percent of a number: useful for discounts, taxes, tips, marks, and commissions.
- What percent: useful when you know the part and the whole.
- Percent change: useful when comparing an old value with a new value.
- Reverse percentage: useful when the final value already includes an increase or decrease.
Example
If a product costs 150 and you want 20% of it, the calculator changes 20% into 0.20, then multiplies 150 × 0.20. The answer is 30.
Percentage formulas
A percentage means “out of 100”. For example, 25% means 25 out of 100, which is the same as 0.25 as a decimal.
| Mode | Formula |
|---|---|
| % of number | (percentage ÷ 100) × number |
| What %? | (part ÷ whole) × 100 |
| % change | ((new − old) ÷ old) × 100 |
| Increase/decrease | number × (1 ± percentage ÷ 100) |
| Reverse % | final ÷ (1 ± percentage ÷ 100) |
| % difference | |a − b| ÷ ((a + b) ÷ 2) × 100 |
Percentage change vs. percentage difference
Percentage change treats the first value as the starting point. Percentage difference treats both numbers equally by comparing their gap with their average. That is why the two answers can be different.