What is the Percentage Difference from 30 to 39?
From 30 to 39 is a 30% increase
Step by step
- Difference: 39 − 30 = 9
- Divide by the starting value: 9 ÷ 30 = 0.3
- Multiply by 100: 30%
How the answer is worked out
Percentage change measures a difference against the value you started with. The value went from 30 to 39, a difference of 9. Compared with the starting value of 30, that difference is 30%, so this is a 30% increase.
The new value is 1.3 times the old one: for every 100 at the start there are now 130.
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 $30 to $39 has gone up by 30%.
- Pay: a wage that rises from $30 to $39 an hour is a 30% pay rise.
- Audiences: a channel that grows from 30 to 39 subscribers has grown by 30%.
A quicker way
Find 1% of the starting value: 30 ÷ 100 = 0.3. The difference of 9 is 30 of those steps.
Percentage change is not the same as percentage points. If a rate moves from 30% to 39%, it changes by 9 percentage points, but by 30% relative to where it started.
Check the answer
Work forwards from the start: 30 × (1 + 0.3) = 30 × 1.3 = 39. Getting 39 shows the answer is right.
Rounding
Rounded to a whole number the change is 30, to one decimal place 30.0 and to two decimal places 30.00. 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: 6 to 24
- Difference: 24 − 6 = 18
- Divide by the starting value: 18 ÷ 6 = 3
- Multiply by 100: 300%
Why the change back is different
A 30% rise followed by a 30% fall does not bring you back to 30: it gives 27.3. The second percentage is taken of 39, not of 30, so to undo this change you need 23.0769% 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 30 to 39
- What percent more is 39 than 30?
- 30 to 39 as a percent change
- How much did 30 grow going to 39, in percent?
- Relative change between 30 and 39
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 | 30% |
|---|---|
| Difference | 9 |
| New ÷ old | 1.3 |
| Direction | increase |
Related results
| 30 to 37 | From 30 to 37 is a 23.3333% increase |
| 30 to 38 | From 30 to 38 is a 26.6667% increase |
| 30 to 40 | From 30 to 40 is a 33.3333% increase |
| 30 to 41 | From 30 to 41 is a 36.6667% increase |
| 30 to 49 | From 30 to 49 is a 63.3333% increase |
The other way round: Percentage difference from 39 to 30
Doing it in a spreadsheet
In Excel, Google Sheets or Numbers type =(39-30)/30*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
| 6 to 24 | Show answerFrom 6 to 24 is a 300% increase |
| 10 to 37 | Show answerFrom 10 to 37 is a 270% increase |
| 78 to 23 | Show answerFrom 78 to 23 is a 70.5128% decrease |
| 32 to 14 | Show answerFrom 32 to 14 is a 56.25% decrease |
| 36 to 6 | Show answerFrom 36 to 6 is a 83.3333% decrease |
| 94 to 23 | Show answerFrom 94 to 23 is a 75.5319% decrease |
| 20 to 39 | Show answerFrom 20 to 39 is a 95% increase |
| 94 to 80 | Show answerFrom 94 to 80 is a 14.8936% decrease |
| 83 to 46 | Show answerFrom 83 to 46 is a 44.5783% decrease |
| 60 to 72 | Show answerFrom 60 to 72 is a 20% increase |
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.
Reference this page
Copy a citation or link:
<a href="https://sumwisemath.com/calc/percentage-change/difference-from-30-to-39/">What is the Percentage Difference from 30 to 39?</a>
"What is the Percentage Difference from 30 to 39?". Sumwise. https://sumwisemath.com/calc/percentage-change/difference-from-30-to-39/
Questions
What is the Percentage Difference from 30 to 39?
Going from 30 to 39 is a 30% increase. Formula and steps.
Is going from 30 to 39 an increase or a decrease?
An increase: the value grew by 9, which is 30% of the starting value.
What is the percentage change from 39 back to 30?
-23.0769%. It is a different number because the starting value is now 39, not 30.
What is the percentage difference between 30 and 39?
When neither value is the starting point, use the average as the base: 9 ÷ 34.5 × 100 = 26.087%. 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 30%.