Original value before a percentage increase
Enter the current value and the percentage it rose by to recover what it was beforehand.
Undoing an increase
An increase makes the new figure more than 100% of the old one. A 12% rise leaves you at 112%, so dividing by 1.12 returns the original. Subtracting 12% does not — it takes 12% of the larger number and lands you below where you started.
A salary is £28,000 after a 12% rise.
- 28,000 ÷ 1.12 = £25,000
- The rise was worth £3,000
- Check: £25,000 + 12% = £28,000 ✓
Taking 12% off £28,000 gives £24,640 — £360 out, and it understates the raise rather than overstating it, which is the direction nobody checks.
Several increases in a row
Rises compound. Three years of 3%, 4% and 5% is not 12% — it is 1.03 × 1.04 × 1.05 = 1.12476, so a figure that has been through all three should be divided by 1.12476 to recover the starting point. The difference looks trivial until the base is large or the years are many.
For the same rate repeated, use a power: five years at 4% is 1.04⁵ = 1.216653. This is the same arithmetic behind compound interest, inflation adjustment and depreciation. The only thing that changes is whether the multiplier sits above or below 1.
Percent or percentage points?
This distinction decides which calculation you need, and it is the single most common way a reverse-percentage answer comes out wrong for a reason that has nothing to do with the arithmetic.
A rate moving from 10% to 15% has risen five percentage points. As a percentage change it has risen 50%, because five is half of ten. Both descriptions are correct and they mean completely different things. If a source says a figure "rose 5%", divide by 1.05; if it says it "rose 5 percentage points", you are not reversing a percentage change at all — you subtract.
Interest rates, tax bands, unemployment and market share are usually quoted in points, while salaries, prices and volumes are quoted in percent. This calculator works in percent throughout: it always treats the figure you enter as a relative change against the original value.
Where this comes up
Pay negotiations. Knowing the base a percentage was applied to tells you what the next percentage will actually be worth.
Rent and contract renewals. An index-linked increase is far easier to sanity-check backwards than forwards, because you already know where it landed.
Real versus nominal figures. Dividing by cumulative inflation converts a present-day figure into its equivalent in an earlier year of money, which is the only fair way to compare the two.
Frequently asked questions
How do I find my salary before a pay rise?
Divide your current salary by 1 plus the rise as a decimal. After a 4% rise to £41,600, the previous salary was 41,600 ÷ 1.04 = £40,000.
How do I reverse two years of increases?
Multiply the multipliers and divide once. A 3% rise followed by a 5% rise is 1.03 × 1.05 = 1.0815, so divide by 1.0815 rather than by 1.08.
What if the increase was more than 100%?
An increase of 150% means the new figure is 250% of the old, so divide by 2.5. The increase adds to the original 100% rather than replacing it.
Does this work for compound interest?
Yes. For a fixed annual rate over n years, divide by (1 + rate) to the power of n. At 5% over three years, divide by 1.05³ = 1.157625.