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Percentage Change Calculator

Calculate percentage change online — free, step by step. From an old and new value get the increase or decrease in percent with full working.

Quick answer
How do you calculate percentage change?
Percentage change is the difference between the new and old value, divided by the old value, times 100: (new − old) ÷ old · 100. A positive result is an increase, a negative one a decrease. Example: from 200 to 250 that is (250 − 200) ÷ 200 · 100 = +25%.
The tool

Enter values — get full working

Comma or dot as decimal separator, negative values allowed.
Step-by-step
Press Calculate to see every step.
HowTo

Percentage Change Calculator — step-by-step

How do you calculate percentage change?
  1. 1
    Step 1 of 4

    Identify the old and new value

    Decide which value is the starting (old) value and which is the end (new) value. Percentage change is always relative to the old value. Example: old = 200, new = 250.

  2. 2
    Step 2 of 4

    Take the difference

    Subtract the old value from the new one: 250 − 200 = 50. A positive result means an increase, a negative one a decrease.

  3. 3
    Step 3 of 4

    Divide by the old value

    Divide the difference by the old value: 50 ÷ 200 = 0.25. That is the relative change as a decimal.

  4. 4
    Step 4 of 4

    Multiply by 100

    Multiply by 100: 0.25 · 100 = 25. The percentage change is +25%.

Examples

Percentage Change Calculator — examples

Worked examples with full working
200 → 250
(250 − 200) ÷ 200 · 100
= 50 ÷ 200 · 100
+25%
250 → 200
(200 − 250) ÷ 250 · 100
= −50 ÷ 250 · 100
−20%
80 → 120
(120 − 80) ÷ 80 · 100
+50%
1,200 → 900
(900 − 1200) ÷ 1200 · 100
−25%
50 → 50
(50 − 50) ÷ 50 · 100
0%
19 → 23.75
(23.75 − 19) ÷ 19 · 100
+25%
Theory

What is percentage change?

Percentage change measures how much a value has changed relative to its starting point. It is defined as (new value − old value) ÷ old value · 100 and expressed in percent. The reference is always the old value (100%). A positive sign means an increase, a negative one a decrease. Note: a 25% increase followed by a 25% decrease does not return to the starting value, because the reference changes. Percentage change underpins growth rates, inflation, returns and price comparisons.

Pitfalls

Common mistakes

Wrong reference value

Change is relative to the old value, not the new one. From 200 to 250 is +25%, but from 250 to 200 is −20%.

Increase and decrease don't cancel

+25% then −25% does not return to the start, because the second percent acts on a different value.

Percent vs percentage points

A share rising from 20% to 25% is +5 percentage points, but +25% relative.
FAQ

Frequently asked questions

Glossary

Glossary — key terms explained simply

Whole (base)
The reference value that equals 100%.
Part (value)
The amount that belongs to a percentage.
Rate
The percentage (per hundred).
Difference
The result of a subtraction (new − old).
Relative
Expressed against a reference, dimensionless.
Absolute
In the unit of the quantity, without reference.
Factor
Number you multiply by (e.g. 1.25 for +25%).
Percentage point
Absolute difference between two percentages.