Percentage Increase Calculator | Between Two Numbers or Add %
Find the percentage increase between two numbers, or add any percentage to a number. Shows the difference, the new value and the calculation step by step.
Common examples
| Calculation | Increase | New value |
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How to calculate the percentage increase between two numbers
To find the percentage increase between two numbers, subtract the original value from the new value, divide the difference by the original value, and multiply by 100. Going from 200 to 230 is a 15% increase: (230 − 200) ÷ 200 × 100 = 15.
Increase % = ((New value − Original value) ÷ |Original value|) × 100
The three steps, in order:
- Subtract the original value from the new value. That is the difference.
- Divide the difference by the original value.
- Multiply by 100 to turn the ratio into a percentage.
Worked example: a salary goes from 36,000 to 45,000. The difference is 45,000 − 36,000 = 9,000. Divided by the original value, 9,000 ÷ 36,000 = 0.25. Multiplied by 100, that is a 25% increase.
If the new value is lower than the original, the result comes out negative. A negative percentage increase is a decrease, and the size of the drop is the same number without the minus sign.
| From | To | Increase | Context |
|---|---|---|---|
| 200 | 230 | 15% | Price before and after a rise |
| 85 | 100 | 17.65% | Two test scores |
| 36 | 45 | 25% | Hours worked per week |
| 50,000 | 52,500 | 5% | Salary after a raise |
| 2,400,000 | 2,640,000 | 10% | House price over a year |
| 50 | 40 | −20% | A decrease, not an increase |
How to increase a number by a percentage
The formula has two parts. First, find the increase amount by multiplying the original value by the percentage divided by 100. Then add it to the original.
Increase amount = Original value × (Percentage ÷ 100)
New value = Original value + Increase amount
Or equivalently: New value = Original value × (1 + Percentage ÷ 100)
For example, increasing 500 by 20% means multiplying 500 by 0.20 to get 100, then adding that to 500 for a result of 600. The multiplier shortcut is 500 × 1.20 = 600.
When you need this calculation
Adding a percentage to a number comes up in surprisingly many contexts. Salary negotiations often involve a proposed raise like "5% increase on your current base." Retail pricing uses it when applying a markup or adding sales tax. Investment growth projections require repeated percentage additions — if your portfolio returned 8% this year, you need to add 8% to last year's value to find the new balance.
In business, price increases are typically communicated as percentages. Knowing the actual dollar amount behind "a 12% supplier price hike" tells you the real cost impact. This calculator does that conversion instantly.
Just as often you have two numbers instead of a percentage, and the percentage is what you are missing. A salary raise from 50,000 to 52,500 is the classic case: the letter states both figures and never the 5%. A price increase works the same way — the supplier sends the old and the new price, and you work out the percentage yourself. So does a house price: bought at 2,400,000 and valued at 2,640,000 a year later is a 10% increase.
Percentage increase vs. percentage change — what's the difference?
Percentage change is the general term for the gap between two values expressed as a percentage. When the new value is higher, that change is a percentage increase; when it is lower, it is a percentage decrease. All three use the same arithmetic — difference divided by the original, times 100 — so the only thing that separates them is the sign of the answer.
This calculator does both jobs. The first mode takes two values and gives you the percentage between them; the second takes one value and a percentage and gives you the result. A negative answer in the first mode means the new value is lower, and the calculator says so in words. If the drop is what you are working with from the start, the percentage decrease calculator frames the same numbers as a reduction.
Quick mental math shortcuts
For a 10% increase, move the decimal point one place left and add that to the original. For 5%, halve the 10% result. For 1%, move the decimal two places left. These building blocks let you estimate most common percentages in your head.
Example: 15% of 800. 10% is 80, 5% is 40, so 15% is 120. The new value is 920. For exact figures or less round numbers, the calculator above saves you the arithmetic.
Frequently asked questions
What is the percentage increase from 85 to 100?
17.65%. The difference is 100 − 85 = 15. Divided by the original value, 15 ÷ 85 = 0.176470588. Multiplied by 100 that is 17.6470588%, which rounds to 17.65%.
How do I calculate a salary raise in percent?
Subtract the old salary from the new one, divide by the old salary, and multiply by 100. A raise from 50,000 to 52,500 is 5%: (52,500 − 50,000) ÷ 50,000 × 100 = 5. Use gross figures for both, or the percentage will not match what your employer quoted.
How do I increase 500 by 20%?
Multiply 500 by 20/100 (which is 0.20) to get the increase amount: 100. Add that to 500 and you get 600. The shortcut: 500 × 1.20 = 600.
Can I use this for negative starting values?
Yes. A 20% increase on −500 gives −500 + (−500 × 0.20) = −500 + (−100) = −600. The value moves further from zero in the negative direction, which is mathematically correct: the magnitude increases by 20%.
What if the percentage is over 100%?
A 200% increase on 50 means 50 × 2.00 = 100 added to the original, giving 150. The new value is three times the original (the original plus twice the original). Any percentage above 100% means the increase alone exceeds the starting value.
Is adding 25% then removing 25% the same as the original?
No. If you increase 100 by 25% you get 125. Decreasing 125 by 25% gives 93.75, not 100. This happens because the 25% decrease is calculated on the larger number (125), so it removes more than was added. The round-trip is never neutral unless the percentage is 0%.
How do I calculate percentage increase in Excel?
For the increase between two numbers, put the original value in A1 and the new value in B1, then enter =(B1-A1)/A1 in C1 and format that cell as a percentage. To add a percentage instead, put the original value in A1 and the percentage in B1 (as a whole number like 20), then enter =A1*(1+B1/100) in C1. For the increase amount alone, use =A1*B1/100.