Most percentage questions fall into one of three types. The calculator above handles all three — select the type that matches your question.
Use this when you want to find a share or fraction of a value.
Formula: Result = (X ÷ 100) × Y
Examples: 15% of $80 = $12. 7% VAT on $200 = $14. 30% off a $150 item saves $45.
Use this when a value has changed and you want to express the change as a percentage.
Formula: Change % = (New value − Original value) ÷ Original value × 100
A positive result means an increase; a negative result means a decrease.
| Original | New value | Change |
|---|---|---|
| $100 | $120 | +20% |
| $100 | $85 | −15% |
| 50 | 75 | +50% |
| 200 | 150 | −25% |
Use this to express one number as a percentage of another — for example, to find what percentage of a class passed an exam, or what share of a budget was spent.
Formula: Percentage = (X ÷ Y) × 100
Examples: 45 out of 60 students passed = 45 ÷ 60 × 100 = 75%. $35 spent out of a $140 budget = 25%.
| Question | Type to use | Example |
|---|---|---|
| How much is the discount? | X% of Y | 20% of $90 = $18 |
| How much has the price risen? | Increase/Decrease | $80 → $96 = +20% |
| What share of the total is this? | What % is X of Y | 30 of 120 = 25% |
| What is the tax amount? | X% of Y | 8% of $250 = $20 |
| How much did sales fall? | Increase/Decrease | 500 → 400 = −20% |
Multiply the number by the percentage and divide by 100. For 15% of $60: 60 × 15 ÷ 100 = $9. Or equivalently, multiply by the decimal: 60 × 0.15 = $9.
Subtract the original value from the new value, divide by the original value, then multiply by 100. From $80 to $100: (100 − 80) ÷ 80 × 100 = 25% increase.
Same formula as increase. From $100 to $75: (75 − 100) ÷ 100 × 100 = −25%. The negative sign indicates a decrease.
Yes. A 150% increase means the new value is 2.5 times the original. If a company's revenue grows from $1M to $2.5M, the increase is 150%. Percentages above 100% are common in growth, investment return, and ratio contexts.
A percentage point is the arithmetic difference between two percentages. If interest rates rise from 3% to 5%, that is a 2 percentage point increase — but a 66.7% increase in the rate itself. The two terms are often confused but mean very different things.