Percentage change calculator
Enter a starting value and an ending value to get the percentage change — positive for growth, negative for decline. Track stock moves, salary raises, website traffic swings, and exam score improvements. The formula uses the original value as the baseline, which is the standard for percent change reporting.
Start value
End value
Result
+25%
How to calculate percentage change
1. Enter the original (old) value.
2. Enter the new value.
3. Read the percent change — positive means increase, negative means decrease.
4. Swap values mentally to see change in the opposite direction.
Percent change examples
Price increase
A product rose from $40 to $52. Change: ((52 − 40) ÷ 40) × 100 = +30%.
Traffic drop
Monthly visits fell from 12,000 to 9,000. Change: ((9000 − 12000) ÷ 12000) × 100 = −25%.
Salary raise
Pay went from $55,000 to $60,500. Change: ((60500 − 55000) ÷ 55000) × 100 ≈ +10%.
When to use percentage change
• When you report KPI growth in dashboards or slide decks.
• When you compare before/after prices during sales analysis.
• When you evaluate investment or portfolio performance over a period.
When to choose something else
• When you need compound growth over multiple periods — use CAGR or compound interest tools.
• When you need "what percent is X of Y" without a time dimension — use the percentage calculator.
• When the baseline value is zero — percent change is undefined; use absolute difference instead.
Relative change vs absolute change
Absolute change is New − Old (dollars, users, points). Relative change expresses that difference as a fraction of the starting point. A site gaining 100 users from a base of 200 (+50%) is a very different story than gaining 100 from 1,000,000 (+0.01%) — relative change captures that context.
Reporting tips for business metrics
Always state the time window and baseline. "Revenue up 20%" should mean compared to last quarter or last year, not an arbitrary number. When baselines are small, pair percent change with absolute numbers to avoid exaggerating noise.
Frequently asked questions
What is the percentage change formula?
((New − Old) ÷ Old) × 100. The old value is always the denominator.
Why is going from 100 to 75 not the same as 75 to 100?
Percent change is asymmetric. 100→75 is −25%; 75→100 is +33.33% because the baseline changed.
Can the result exceed 100%?
Yes. An increase from 10 to 30 is +200%. Large relative growth produces percentages above 100%.
What if the old value is negative?
The math still runs, but interpretation is tricky — discuss absolute values in financial contexts.
Is this the same as percentage points?
No. Moving from 10% to 15% interest is a 5 percentage point increase, but a 50% relative increase.
Is my data uploaded?
No. Calculations run locally in your browser.