Percentage Change Calculator
Calculate percent change between two numbers — positive for increases, negative for decreases. Works for prices, metrics, populations, and anywhere you track movement over time.
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How this works
% Change = ((New − Old) ÷ |Old|) × 100Subtract the old value from the new value, divide by the absolute value of the original, and multiply by 100. Positive means increase, negative means decrease. The absolute-value bars handle the edge case where the original value is negative (e.g., temperatures or account balances).
Examples
Positive change
Website traffic rises from 8,400 to 10,500 monthly visitors. Change = (10,500 − 8,400) ÷ 8,400 = 0.25 = +25%. A 25% month-over-month increase is strong for an established site; early-stage growth numbers often run higher.
Negative change
A stock falls from $100 to $72. Change = (72 − 100) ÷ 100 = −0.28 = −28%. Down-moves are measured against the higher starting price, so a stock that falls 50% needs a 100% rise to recover.
No change
A metric stays at 1,200 two months in a row. Change = (1,200 − 1,200) ÷ 1,200 = 0 = 0%. "Flat" or "unchanged" is the usual term in reports — 0% change signals the underlying driver is stable.
Year-over-year growth
Revenue grows from $4.2M to $6.8M. Change = (6.8 − 4.2) ÷ 4.2 = 0.6190 = +61.9%. YoY percent change is the cleanest way to compare growth rates across businesses of different sizes.
Common questions
No. Percent change has direction — from "old" to "new" — and divides by the old value. Percent difference is symmetric: it divides by the average of the two values and ignores direction. Use change for before/after comparisons (prices, stocks, metrics over time); use difference for comparisons where neither value is the reference.
Percentage change from zero is mathematically undefined. The calculator returns N/A. If the old value is zero and the new value is positive, some people describe it as "infinite growth" or simply report the absolute change. Starting from zero, the percentage framing does not apply.
The base changes. 100 up 50% is 150. 150 down 50% is 75 — not 100. To undo a percent increase, you need a SMALLER percent decrease (and vice versa). A 100% gain is undone by a 50% loss, not another 100%.
Multiply the growth factors together. Three years of +8% growth: 1.08 × 1.08 × 1.08 = 1.2597, so a 25.97% total increase — not 24%. This is why compound returns and compound inflation both accelerate over time.
Yes — whenever the new value is more than double the old. 20 → 100 is a 400% increase. For very large changes, multipliers ("5×") are often more readable than percentages ("400%"), especially in headlines.
No. All calculations happen in your browser. Nothing you type is sent to a server. Your calculation history is stored locally and can be cleared any time.