Calculate percent change from 100 to 80

Calculate percentages: X% of a number, what percent one number is of another, and percent change between values.

What is%of

Answer

20% decrease

To find the percent change from 100 to 80, follow the step-by-step solution below.

Step 1 — Find the difference

Subtract the original value from the new value:

80 − 100 = -20

The value decreased by 20.

Step 2 — Divide by the original value

Divide the change by the original to find the decimal change:

-20 ÷ 100 = -0.2

Step 3 — Convert to a percentage

Multiply by 100 to express as a percentage:

-0.2 × 100 = -20%

20% decrease

Percent change from 100 to 80: subtract the old value from the new, divide by the old value, and multiply by 100.

This is a percentage calculation — percentages express a number as a fraction of 100. To find X% of Y, multiply Y by X/100.

What is the answer to percent change from 100 to 80?
The answer is 20% decrease.

What method is used?
Convert the percentage to a decimal (divide by 100), then multiply. For percent change, use (new − old) / old × 100.