BCBetter Calculators

Percentage Change Calculator

Calculate the percentage increase or decrease between an old value and a new value.

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Enter your values and click Calculate

How It Works

The calculator subtracts the old value from the new value to find the raw numeric difference. That difference is then divided by the absolute value of the original number, which ensures correct sign handling even when the starting value is negative — for example, a recovery from a loss. Multiplying by 100 converts the proportion into a percentage. A positive result means the value increased from old to new, while a negative result means it decreased. The calculator also shows the raw numeric difference alongside the percentage, so you can see both the relative and absolute magnitude of the change at a glance. Note that the original value cannot be zero, since percentage change is mathematically undefined when dividing by zero.

Examples

Price Increase
A subscription goes from $10 a month up to $12.
Result: Shows a 20% increase (a difference of 2).
Weight Loss
A person's weight drops from 200 lbs to 185 lbs.
Result: Shows a -7.5% decrease (a difference of -15).
Negative numbers
A company's profits go from -$50,000 to -$20,000 (an improvement).
Result: Shows a positive 60% change, indicating financial recovery.

Frequently Asked Questions

What does a negative percentage change mean?
A negative percentage change indicates a decrease or drop from the original value. For example, a change from 100 to 75 produces a −25% result, meaning the value fell by a quarter of its original amount.
Why can't the original value be zero?
In mathematics, dividing by zero is undefined. If you start with 0 and gain 10, the percentage growth would be theoretically infinite, so the calculator returns an error rather than a misleading result.
Is percentage change the same as percentage difference?
No. Percentage change specifically measures directional movement from an old value to a new one, using the original as the reference. Percentage difference compares two values symmetrically using their average as the denominator, without implying either value is older.
Can a percentage change be over 100%?
Yes. If a value doubles, that represents a 100% increase. If it triples, the increase is 200%. There is no upper limit on percentage change — values can grow by any multiple of the original.

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