How is percentage change calculated?

Percentage change = ((New Value − Original Value) / |Original Value|) × 100. A positive result means an increase, and a negative result means a decrease. The denominator is always the original (starting) value, not the new value.

Can percentage change exceed 100%?

Yes. If a value doubles, the percentage change is 100%. If it triples, it is 200%. There is no upper limit on percentage increase. Percentage decrease, however, can only reach −100% (where the final value is zero).

What is the difference between percentage change and percentage points?

Percentage points measure the absolute difference between two percentages (5% to 7% = 2 pp). Percentage change measures the relative move (5% to 7% = +40% change). News headlines often blur the distinction; always check whether a story means "percentage points" or "percent change".

Why do gains and losses behave asymmetrically?

A 50% gain followed by 50% loss does not return to the original value. $100 × 1.5 = $150; $150 × 0.5 = $75. To recover a 50% loss requires a 100% gain (doubling). The percentage needed to recover always exceeds the percentage lost. This compounding asymmetry matters greatly in investment returns.

What happens if the original value is zero?

Percentage change is undefined (division by zero). For going from 0 to a positive value, conventionally report as "new value from zero" or "infinite percentage change" — though more practical is just stating the absolute change. Most calculators return an error.

How is percentage change different from percent error?

Same formula structure, different meaning. Percent change: comparing two values where neither is "true" (often before/after). Percent error: comparing measured value to a known correct value. Both use (difference/reference) × 100, but interpret the result differently.

Should I use the original or new value as the base?

Always the original (starting) value. Using the new value gives a different (and usually less meaningful) result. Convention: percentage change is "relative to the starting point." Stick with this to avoid confusion.

Percentage Change Calculator

Find the percentage change between an original value and a new value. Useful for tracking price changes, salary increases, population growth, and any scenario where you need to measure relative change.

Last updated: July 28, 2026

About this calculator

Percentage change measures how much a value has grown or shrunk relative to its starting point. It's the standard way to communicate "how much did X go up or down" in everything from stock prices and inflation reports to a kid's growth chart. The formula is simple, but the direction matters and the choice of "original value" can change the answer.

Use this calculator to compute the percent increase or decrease between any two numbers. Enter the original value and the new value; the calculator returns the percentage change with the correct sign (positive for increase, negative for decrease) and the absolute dollar change.

Formula

Percentage change: Δ% = ((New − Original) / |Original|) × 100 Positive = increase, negative = decrease. The denominator is the absolute value of Original, which keeps the sign of the result tied to the direction of change. Using the new value as denominator gives a different (less useful) measure. Example: salary from $50,000 to $58,000 Δ% = ((58,000 − 50,000) / 50,000) × 100 = 16% Example: house price from $400,000 to $360,000 Δ% = ((360,000 − 400,000) / 400,000) × 100 = −10%

How to use this calculator

Enter the original (starting) value.
Enter the new (current) value.
Read the result: positive means an increase, negative a decrease. The number is the relative change as a percentage of the original.
For percentage-point vs percentage change: if a rate moves from 5% to 7%, that's a 2 percentage-point increase but a 40% percentage change. The two are not the same and the distinction often matters (especially in interest rate or tax discussions).

Worked examples

Raise

Salary moves from $65,000 to $71,500. Change: +$6,500 Percentage change: +10% A 10% raise sounds nice; in real terms it's about a 6–7% raise once inflation and higher taxes are subtracted, but still a meaningful improvement.

Stock decline

Stock drops from $80 to $60. Change: −$20 Percentage change: −25% To get back to break-even from $60 requires a +33% recovery, not +25%. This asymmetry is why drawdowns hurt more than gains help on the way back.

When to use this calculator

Use this anywhere you compare two values and want to express the difference relative to the starting point: price changes, salary growth, weight loss progress, population shifts, investment returns.

Watch out for two related ideas: - Percentage point change: simple subtraction of two percentages (e.g. tax rate from 22% to 24% = +2 percentage points) - Percent change: the relative move (22% to 24% = +9.1%)

Headlines often conflate these to make a number sound larger.

Common mistakes to avoid

Using the new value as the denominator. Always divide by the original.
Confusing percentage points with percent change. A rate "going up 2%" can mean either depending on speaker.
Calculating percentage change with a zero starting value. The math is undefined; report it as "new value from zero" instead.
Averaging percentage changes naively. A 50% gain followed by 50% loss is not zero — it's a 25% loss. Use geometric means for compound percent changes.

Frequently Asked Questions

Sources & further reading

Percent change explained — U.S. Securities and Exchange Commission

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About this calculator

Formula

How to use this calculator

Enter the original (starting) value.

Enter the new (current) value.

Read the result: positive means an increase, negative a decrease. The number is the relative change as a percentage of the original.

For percentage-point vs percentage change: if a rate moves from 5% to 7%, that's a 2 percentage-point increase but a 40% percentage change. The two are not the same and the distinction often matters (especially in interest rate or tax discussions).

Worked examples

Raise

Stock decline

When to use this calculator

Use this anywhere you compare two values and want to express the difference relative to the starting point: price changes, salary growth, weight loss progress, population shifts, investment returns.

Headlines often conflate these to make a number sound larger.

Common mistakes to avoid

Using the new value as the denominator. Always divide by the original.

Confusing percentage points with percent change. A rate "going up 2%" can mean either depending on speaker.

Calculating percentage change with a zero starting value. The math is undefined; report it as "new value from zero" instead.

Averaging percentage changes naively. A 50% gain followed by 50% loss is not zero — it's a 25% loss. Use geometric means for compound percent changes.

Frequently Asked Questions

Percentage Change Calculator

About this calculator

Formula

How to use this calculator

Worked examples

Raise

Stock decline

When to use this calculator

Common mistakes to avoid

Frequently Asked Questions

Sources & further reading

Related Calculators

Percentage Calculator

Fraction Calculator

Square Root Calculator

Exponent Calculator

Logarithm Calculator

Scientific Notation Calculator

Percentage Change Calculator

Inputs

Results

About this calculator

Formula

How to use this calculator

Worked examples

Raise

Stock decline

When to use this calculator

Common mistakes to avoid

Frequently Asked Questions

Sources & further reading

Related Calculators

Percentage Calculator

Fraction Calculator

Square Root Calculator

Exponent Calculator

Logarithm Calculator

Scientific Notation Calculator

Inputs

Results