Percent Change Calculator
Find percent change between two values and apply percentage increase/decrease.
Percent Change
0.00%
Apply Percentage
Increased by %
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Decreased by %
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Informational only; verify critical results independently.
How to use
- Enter the starting (old) value and the ending (new) value for relative change.
- Or enter one value and a percent increase/decrease to apply in one step.
- Read the percent change: positive for growth, negative for decline.
- Use for prices, metrics, populations, or any two comparable measurements.
- Watch the baseline: percent change is always relative to the old value.
- Copy the result for reports; round according to your audience.
Examples
- Stock price $40 → $46 (percent gain)
- Monthly users 10,000 → 12,500 (growth %)
- Apply 8% discount to $89.99 list price
- Salary $75k to $82k raise percentage
- Temperature swing −5 °C to 10 °C (not a ratio—use absolute change for physics)
- Error: old value 0 → undefined percent change
FAQ
- What is the formula?
- Percent change = (new − old) ÷ old × 100%. Swapping old and new flips the sign.
- Why Infinity or NaN?
- Old value 0 makes relative change undefined; both values must be valid numbers.
- Percentage points?
- If you mean points (e.g. rate 2%→3%), that is +1 percentage point but +50% relative to the old rate.
- Can I chain changes?
- Compute stepwise or combine multiplicatively depending on the story you need.
- Negative old values?
- Economics contexts get subtle; interpret sign carefully with negatives.
- Privacy?
- All math runs in your browser.
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Last updated: 2025-09-15