Free Percent Change Calculator Online
This free online percent change calculator computes the percentage change between any two values — positive for increase, negative for decrease.
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Percent Change
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The Percent Change Formula
Percent change measures how much a value has grown or shrunk relative to its original level. This free percent change calculator uses the formula below — calculate online and get instant results:
Percent Change = ((New − Original) / |Original|) × 100
A positive result means an increase; a negative result means a decrease. For example, a price rising from $80 to $100 gives (100−80)/80 × 100 = +25%. A price falling from $100 to $80 gives (80−100)/100 × 100 = −20%.
Notice these aren't symmetric: a 25% increase followed by a 20% decrease gets you back to the start — not a 25% decrease. This asymmetry matters in investing, economics, and performance tracking.
The percent change calculator uses the absolute value of the original in the denominator, which handles negative starting values correctly. If a temperature changes from −10°C to −5°C, that is a 50% increase (it moved closer to zero by half its original magnitude).
Example Calculations
| From | To | Percent Change | Direction |
|---|---|---|---|
| 80 | 100 | +25.00% | Increase |
| 100 | 80 | −20.00% | Decrease |
| 50 | 75 | +50.00% | Increase |
| 200 | 150 | −25.00% | Decrease |
| 1000 | 1050 | +5.00% | Increase |
| 45 | 36 | −20.00% | Decrease |
Common Uses for a Percent Change Calculator
Stock Performance
A stock bought at $45 and now trading at $63: that's a +40% gain. A stock bought at $100 now at $72 is a −28% loss. This free percent change calculator gives you the precise number online, which is more useful than the dollar difference when comparing positions of different sizes.
Price Changes
Groceries that cost $120/week last year now cost $138/week. Our free online percent change calculator tells you that's a 15% increase — which is the number you need to compare against wage growth or inflation statistics, not the $18 difference.
Business Metrics
Monthly active users grew from 4,200 to 5,040: a +20% increase. Revenue dropped from $85,000 to $72,250: a −15% decrease. This free percent change calculator makes reporting growth metrics clear and consistent — use it online to calculate metrics in seconds.
Things to Watch Out For
The Asymmetry Trap
A 50% increase followed by a 50% decrease does not return you to the start. 100 → 150 (+50%) → 75 (−50%). The percent change calculator always uses the current original as the base — not a fixed reference.
Percent Change vs. Percentage Points
If a fund's return went from 4% to 6%, that's a 2 percentage point increase but a 50% relative increase. Headlines often conflate these — the percent change calculator measures the relative version.
Zero Starting Value
Percent change is undefined when the original value is zero. Going from 0 to 100 is "infinite" percentage growth — a mathematically valid observation but not a useful one. Use absolute change instead.
Direction Matters
Always enter the original (earlier) value first and the new value second. Swapping them gives the opposite direction and a different percentage. The percent change calculator is directional by design.
Frequently Asked Questions
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