What is the Percentage Difference from 80 to 100?
From 80 to 100 is a 25% increase
Step by step
- Difference: 100 − 80 = 20
- Divide by the starting value: 20 ÷ 80 = 0.25
- Multiply by 100: 25%
How the answer is worked out
Percentage change measures a difference against the value you started with. The value went from 80 to 100, a difference of 20. Compared with the starting value of 80, that difference is 25%, so this is a 25% increase.
The new value is 1.25 times the old one: for every 100 at the start there are now 125.
Why calculate this?
Percentage change compares a new value with an old one regardless of size: price rises, growth, discounts, score changes.
- Prices: an item whose price rises from $80 to $100 has gone up by 25%.
- Pay: a wage that rises from $80 to $100 an hour is a 25% pay rise.
- Audiences: a channel that grows from 80 to 100 subscribers has grown by 25%.
A quicker way
Find 1% of the starting value: 80 ÷ 100 = 0.8. The difference of 20 is 25 of those steps.
Percentage change is not the same as percentage points. If a rate moves from 80% to 100%, it changes by 20 percentage points, but by 25% relative to where it started.
Check the answer
Work forwards from the start: 80 × (1 + 0.25) = 80 × 1.25 = 100. Getting 100 shows the answer is right.
Rounding
Rounded to a whole number the change is 25, to one decimal place 25.0 and to two decimal places 25.00. Round only at the end: rounding halfway through a calculation can change the last digit.
The formula explained
percentage change = (new value − old value) ÷ old value × 100. A positive result is an increase and a negative result is a decrease. The old value is always the base, which is why the change from A to B and from B to A are different percentages.
Another worked example: 16 to 2
- Difference: 2 − 16 = -14
- Divide by the starting value: -14 ÷ 16 = -0.875
- Multiply by 100: -87.5%
Why the change back is different
A 25% rise followed by a 25% fall does not bring you back to 80: it gives 75. The second percentage is taken of 100, not of 80, so to undo this change you need 20% instead.
Other ways to ask this
The same calculation is often asked in other words. All of these have the answer above:
- Percentage increase from 80 to 100
- What percent more is 100 than 80?
- 80 to 100 as a percent change
- How much did 80 grow going to 100, in percent?
- Relative change between 80 and 100
Terms used on this page
- Old value: the starting amount, used as the base of the percentage.
- New value: the amount after the change.
- Increase: a positive change: the new value is bigger.
- Percentage point: the plain difference between two rates, not a relative change.
The answer in other forms
| Change | 25% |
|---|---|
| Difference | 20 |
| New ÷ old | 1.25 |
| Direction | increase |
Related results
| 80 to 98 | From 80 to 98 is a 22.5% increase |
| 80 to 99 | From 80 to 99 is a 23.75% increase |
| 80 to 101 | From 80 to 101 is a 26.25% increase |
| 80 to 102 | From 80 to 102 is a 27.5% increase |
| 80 to 110 | From 80 to 110 is a 37.5% increase |
The other way round: Percentage difference from 100 to 80
Doing it in a spreadsheet
In Excel, Google Sheets or Numbers type =(100-80)/80*100 into any cell. Replace the numbers with cell references (for example A1 and B1) to reuse the formula for a whole column.
Common mistakes
Always divide by the starting value, not the new one. A rise from 40 to 50 is +25%, but the fall from 50 back to 40 is −20%.
Practice examples
| 16 to 2 | Show answerFrom 16 to 2 is a 87.5% decrease |
| 58 to 77 | Show answerFrom 58 to 77 is a 32.7586% increase |
| 23 to 64 | Show answerFrom 23 to 64 is a 178.2609% increase |
| 30 to 34 | Show answerFrom 30 to 34 is a 13.3333% increase |
| 29 to 61 | Show answerFrom 29 to 61 is a 110.3448% increase |
| 97 to 34 | Show answerFrom 97 to 34 is a 64.9485% decrease |
| 45 to 81 | Show answerFrom 45 to 81 is a 80% increase |
| 54 to 82 | Show answerFrom 54 to 82 is a 51.8519% increase |
| 54 to 27 | Show answerFrom 54 to 27 is a 50% decrease |
| 65 to 15 | Show answerFrom 65 to 15 is a 76.9231% decrease |
How this answer was calculated
The result is worked out from the numbers in this page's address when the page is opened, using exact arithmetic wherever possible and rounding only for display. Nothing is copied from a printed table. If you think an answer is wrong, please tell us through the contact page and we will check it.
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Questions
What is the Percentage Difference from 80 to 100?
Going from 80 to 100 is a 25% increase. Formula and steps.
Is going from 80 to 100 an increase or a decrease?
An increase: the value grew by 20, which is 25% of the starting value.
What is the percentage change from 100 back to 80?
-20%. It is a different number because the starting value is now 100, not 80.
What is the percentage difference between 80 and 100?
When neither value is the starting point, use the average as the base: 20 ÷ 90 × 100 = 22.2222%. That is the symmetric percentage difference.
How do I calculate percentage change in Excel or Google Sheets?
Put the old value in A1 and the new value in B1, then type =(B1-A1)/A1 and format the cell as a percentage. For these numbers it shows 25%.