How to calculate a percentage increase
A percentage increase says how much bigger a number became, as a share of where it started. There are three steps:
In one line: percentage increase = (new − old) ÷ old × 100. Statistical agencies use the same method: subtract the earlier value from the later one, divide by the earlier value, and multiply by 100.1 If the answer is negative, the number went down, and it is a percentage decrease.
Percentage increase examples
The same formula covers a raise, a rent rise, a price change or growth in a count. The step-by-step working for your own numbers is shown in the calculator above.
| What | Old | New | Increase | Percentage increase |
|---|---|---|---|---|
| A salary | $52,000 | $54,600 | $2,600 | 5% |
| A monthly rent | $1,200 | $1,290 | $90 | 7.5% |
| A price | $80 | $92 | $12 | 15% |
| A town's population | 12,500 | 13,125 | 625 | 5% |
| A website's monthly visitors | 3,000 | 4,200 | 1,200 | 40% |
The 250 to 300 example gives 20%, but going back from 300 to 250 is a decrease of 16.67%, not 20%: the base is different each way, which is why a percentage increase and the matching decrease are never the same number.
How to increase a number by a percentage
Multiply the number by 1 plus the percent as a decimal: number × (1 + percent ÷ 100). To increase 200 by 15%, multiply by 1.15 to get 230. The table has the result for some common starting numbers and increases.
| Starting number | +5% | +10% | +15% | +20% | +25% | +50% | +100% |
|---|---|---|---|---|---|---|---|
| 100 | 105 | 110 | 115 | 120 | 125 | 150 | 200 |
| 250 | 262.5 | 275 | 287.5 | 300 | 312.5 | 375 | 500 |
| 500 | 525 | 550 | 575 | 600 | 625 | 750 | 1,000 |
| 1,000 | 1,050 | 1,100 | 1,150 | 1,200 | 1,250 | 1,500 | 2,000 |
| 5,000 | 5,250 | 5,500 | 5,750 | 6,000 | 6,250 | 7,500 | 10,000 |
| 50,000 | 52,500 | 55,000 | 57,500 | 60,000 | 62,500 | 75,000 | 100,000 |
How to find the original number before an increase
Divide the final number by 1 plus the percent as a decimal. A price of 120 after a 20% increase was 120 ÷ 1.2 = 100. The common mistake is to take 20% off 120, which gives 96: the 20% was added to the smaller original, so it is a smaller share of the final price. Use "Find the original" above to do it for any numbers.
When a percentage increase looks wrong
- The old value is 0. A percentage increase from zero is undefined, because you cannot divide by zero. Report the absolute change instead.
- The old value is negative. Divide by the size of the old value, ignoring its sign. From -50 to -25 the number rose by 25, which is an increase of 50%. Dividing by -50 itself would give the wrong sign.
- A 200% increase means three times as big. Going from 100 to 300 adds 200, which is 200% of the start. The new value is 300% of the old one, but the increase is 200%.
- Percent versus percentage points. If a rate rises from 5% to 6%, that is a 1 percentage point rise and a 20% increase. The percentage change calculator explains the difference.
- Index numbers. The U.S. Bureau of Labor Statistics' worked example takes index values of 278.802 and 296.797 twelve months apart, a rise of 6.5%.1
In Excel or Google Sheets
With the old value in A1 and the new value in B1, the percentage increase is =(B1-A1)/A1, formatted as Percent. To increase A1 by the percent in B1, use =A1*(1+B1). If the old value can be negative, use =(B1-A1)/ABS(A1).
Frequently asked questions
How do I calculate percentage increase?
Subtract the old value from the new value, divide by the old value, and multiply by 100. From 250 to 300: (300 − 250) ÷ 250 × 100 = 20%.
What is the percentage increase from 250 to 300?
It is 20%. The number rose by 50, and 50 is 20% of the starting 250.
How do I increase a number by a percentage?
Multiply it by 1 plus the percent as a decimal. Increasing 200 by 15% is 200 × 1.15 = 230. The table above shows other starting numbers and percentages.
What does a 200% increase mean?
The number grew by twice its starting size, so it ends up three times as big: 100 becomes 300. A 100% increase doubles a number, and a 300% increase makes it four times as big.
How do I work out a salary or rent increase as a percentage?
Use the old and new amounts. A salary going from $52,000 to $54,600 is an increase of 5%; a rent going from $1,200 to $1,290 is an increase of 7.5%.
How do I find the original number before a percentage increase?
Divide the final number by 1 plus the percent as a decimal. If the final number is 120 after a 20% increase, the original is 120 ÷ 1.2 = 100. Taking 20% off 120 would give 96, which is wrong.
Why can't I calculate a percentage increase from zero?
The formula divides by the old value, and dividing by zero is undefined. A rise from 0 to anything is not a percentage of the starting point, so describe it as an absolute change.
What if the number went down?
The result is negative and the calculator calls it a decrease. From 300 to 250 is a decrease of 16.67%. The percentage change calculator is built for changes in either direction.
How do I calculate percentage increase in Excel?
With the old value in A1 and the new value in B1, enter =(B1-A1)/A1 and format the cell as Percent. Use =(B1-A1)/ABS(A1) if the old value can be negative.
Is what I type sent anywhere?
No. The calculation runs in your browser and the numbers you enter are not sent to a server. We count page visits with our own analytics on our own server, and those events carry no amounts or inputs.
Sources
- U.S. Bureau of Labor Statistics, Calculating percent changes (last modified February 9, 2023): the method, and a worked example using index values of 278.802 (December 2021) and 296.797 (December 2022).
Every answer and table on this page is calculated by this page's own code, which is checked against an independent implementation in the site's test suite.