Percentage change

Percentage change from 80 to 100

Going from 80 to 100 is a 25% increase. See the working, the multiplier and the percentage needed to reverse it.

80 → 100

+25%

Step-by-step working

Find the difference: 100 − 80 = 20.
Divide by the starting value: 20 ÷ 80 = 0.25.
Multiply by 100: 0.25 × 100 = 25%.

In real life

As a price

A price moving from $80 to $100 is a 25% increase of $20.

As a multiplier

100 is 80 × 1.25. Multiplying by 1.25 applies this exact change.

Reversing it

To get from 100 back to 80 you need a 20% decrease — not 25%, because the base changed.

Other ways to write it

Difference	20
Multiplier	× 1.25
Reverse change	-20%

What is the change from 100 to 80? -20%. Percentage changes are not symmetrical: the base is different each way.

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Frequently asked questions

What is the percentage change from 80 to 100?

+25% — a 25% increase. Formula: (new − old) ÷ old × 100.

Why is a percentage decrease not the reverse of the increase?

Because each percentage is measured against a different starting value. Here the change is 25% one way and -20% the other.

What does a negative percentage change mean?

The value went down. −20% means it fell by a fifth of its original value.

Is percentage change the same as percentage difference?

No. Percentage change has a direction (old → new) and divides by the old value. Percentage difference is symmetrical and divides by the average of the two values.