Percentage Change Calculator
The percentage increase or decrease between two values.
Your figures
Result
How to use this tool
- Enter your own figures over the defaults — Original value, New value.
- The answer updates as you type. There is no button, and nothing is sent anywhere.
- Change one input at a time to see how sensitive the answer is to it.
Percentage changes are not symmetrical. A 50% fall needs a 100% rise to return to where it started — which is why investment losses hurt more than equivalent gains help.
How it works
This takes 2 inputs — original value, new value — and returns increase, absolute change and new as % of original. The whole calculation happens in this page as you type: there is no submit button, no request, and nothing stored.
A worked example
Worked through with the figures the page already has in it: original value of 200 and new value of 250, giving increase of 25.0%. These numbers come from running the calculator’s own code, not from being typed in here, so they cannot drift away from what you see on screen.
Starting from:
- Original value: 200
- New value: 250
| Result | Value |
|---|---|
| Increase | 25.0% |
| Absolute change | 50.00 |
| New as % of original | 125.0% |
Percentage Change Calculator — frequently asked questions
What is the formula?
(New − Original) ÷ Original × 100. A positive result is an increase, negative a decrease.
Why is a 50% loss not fixed by a 50% gain?
Because the gain is calculated on the reduced amount. £100 falling 50% is £50; a 50% gain on £50 is only £75. You need 100% to get back.
What is the difference from percentage points?
Moving from 5% to 7% is a 2 percentage point rise but a 40% increase. Financial reporting often confuses the two.
Is this calculator free?
Yes, with no account, no limits and no data collection. It runs entirely in your browser.
Should I rely on this for a financial or medical decision?
No. It is a planning estimate built on standard formulas and stated assumptions. For decisions that matter, speak to a qualified professional who can account for your full circumstances.
Is this calculator accurate?
The arithmetic is exact — it uses the standard formula. What limits accuracy is the assumptions: the figures you enter, and factors the formula does not model such as fees, taxes and rule changes.
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Background reading: Loan, Mortgage and Investment Calculators Explained
Nothing is sent anywhere. The figures you type stay in this page and are never transmitted or stored — how that works.
Disclaimer. The formula is exact; the answer is only as good as the figures and assumptions above. Not financial, tax, medical or legal advice. Full disclaimer.