MihsabaA percentage question can ask for a share, a rate, a change, or the original amount. Identify which number is the base before calculating. Applying a rate to the wrong base is the most common reason answers differ.
Formula
Percent of value = value × rate / 100; part as percent = part / total × 100; price after discount = price × (1 − rate / 100).
How to calculate
- Identify the base value that the percentage acts on.
- Convert the rate to a decimal by dividing by 100.
- Apply the matching formula and verify by reversing the operation.
Worked examples
| Scenario | Calculation | Answer |
|---|---|---|
| 15% of 240 | 240 × 0.15 | 36 |
| 45 out of 60, in percent? | 45 / 60 × 100 | 75% |
| 20% discount on 150 | 150 × 0.8 | 120 |
| 12% increase on 200 | 200 × 1.12 | 224 |
Important limitation
A 20% increase followed by a 20% decrease does not cancel out: 100 becomes 120 then 96. A part/whole percentage is undefined if the whole is zero.
Common question
Is percentage the same as percentage change?
No. Percentage change compares a new value to an old one; percent of a value determines a share of one base.
Try the calculator: Percentage Calculator – 6 Free Calculation Modes