How to Calculate Percentages: The Complete Guide
Master every kind of percentage problem — finding a percentage of a number, percentage change, increases and decreases, working backwards, and the traps that catch people out — with clear examples.
Percentage Calculator
Verified formula Updated Jun 2026 Private — runs on your device
Verified formula
Private
Result (X% of Y)
50.00
- Value increased by X%
- 550.00
- Value decreased by X%
- 450.00
For general information only — not financial, tax, legal or medical advice. Verify before you rely on it.
How to use the Percentage Calculator
The Percentage Calculator works out your result (x% of y), along with 2 related figures in an instant. Enter percentage and of value and the result updates as you type — it is free, needs no sign-up, and runs entirely in your browser so your figures stay private.
- Enter the percentage.
- Enter the of value.
- Read off your result (x% of y), together with value increased by x% and value decreased by x% — the calculator updates automatically, with no button to press.
Formula
The Percentage Calculator uses the formula:
Result (X% of Y) = Of value × Percentage ÷ 100
Worked example
For example, with percentage of 10 % and of value of 500, the result (x% of y) is 50.00.
| Percentage | 10 % |
|---|---|
| Of value | 500 |
| Result (X% of Y) | 50.00 |
|---|---|
| Value increased by X% | 550.00 |
| Value decreased by X% | 450.00 |
Results are estimates for educational use, not professional advice.
Key terms explained
- Percentage
- A number expressed as a fraction of 100, written with the % sign.
Frequently asked questions
Multiply the number by the percentage and divide by 100. For example, 10% of 500 = 500 × 10 / 100 = 50. The calculator does this instantly and also shows increase and decrease results.
Divide the first number by the second and multiply by 100. For example, 50 is what percent of 500? 50 / 500 × 100 = 10%.
Percentage change = (new − old) / old × 100. A positive result is an increase and a negative result is a decrease. This calculator also shows a value after applying a given percent up or down.
It means a portion of Y equal to X hundredths. For instance, 18% of ₹1,000 is the part of ₹1,000 that corresponds to 18 per 100, which equals ₹180.
Enter the percentage. Enter the of value. Read off your result (x% of y), together with value increased by x% and value decreased by x% — the calculator updates automatically, with no button to press.
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