Reverse percentage calculator UK
Recover the starting value before a known percentage increase or decrease. Check the formula, worked example and limits before using your own figures.
Enter your figures
Original value before the change
Inputs changed. Select Calculate result to update your estimate.
Use your actual figures. Any prefilled price, fee, rate or return is an editable illustration, not a current product quote. One percentage change from a positive base. The decrease is limited below 100% to avoid division by zero.
How the reverse percentage calculator uk works
Original = final ÷ (1 + increase) or final ÷ (1 − decrease).
Data basis: mathematical formula using your inputs. Example prices and rates are illustrative, not current market quotes.
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Worked example: reverse percentage
This illustration uses the calculator’s example inputs. It is not a quote or a recommended financial decision.
- Final value
- 120
- Percentage change (%)
- 20
- What happened to the original value?
- It increased
Original value before the change: 100 units
Original = final ÷ (1 + increase) or final ÷ (1 − decrease).
Reverse percentage: questions answered
What does the reverse percentage calculation include?
Original = final ÷ (1 + increase) or final ÷ (1 − decrease). Use your actual figures. Any prefilled price, fee, rate or return is an editable illustration, not a current product quote. One percentage change from a positive base. The decrease is limited below 100% to avoid division by zero.
Using your result
Example inputs are a starting point. Replace them with your figures and select Calculate result. Results are rounded for display; calculations use unrounded values.
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