Discount calculator
Combine discounts, shipping and taxes and compare final prices.
FINANCEPercentage calculator
Calculate proportions, increases, decreases and changes between values.
Your starting point
Apply to prices, discounts and taxes
Your result
Editable example; you have not calculated your own inputs yet.
Result20
View full table · 1 rows
| Item | Value |
|---|---|
| Result | 20 |
Method and assumptions
Percentage of an amount: base × percentage / 100. Increases and decreases: base × (1 ± percentage / 100).
Change = (second value − base) / absolute base × 100. Ratio = second value / base × 100.
What if you change the plan?
Keep this result, change your inputs and compare.
Worked example and interpretation
20% of 150 is 150 × 20 / 100 = 30. Increasing 150 by 20% gives 180; reducing it by 20% gives 120. These are different operations on the same inputs. Going from 120 to 150 is (150 − 120) / 120 × 100 = 25%.
What to check
Percentages depend on the base. A 20% rise followed by a 20% fall does not restore the original amount: 100 → 120 → 96. Rates of 4% and 5% differ by 1 percentage point, but the relative increase is 25%.