The Percentage Increase Calculator helps you measure how much a value rose from a starting point to a new amount, shown as a percentage of the original value. It’s quick and convenient, but it also helps to know the simple math behind it. Once you understand the formula, you can spot-check results and feel confident you’re using the right inputs.
How to calculate percent increase
Percent increase tells you how much something grew compared to where it started, using 100 parts as the reference point. A 5% increase means the original amount grew by 5 parts out of every 100 parts.
So if a value goes up by 14%, that means:
- 14 more for every 100 units
- 28 more for every 200 units
- and so on
Next, we’ll walk through the formula with a clear example.
While the Percentage Increase Calculator is common in math, it also shows up in science. For example, you might use percent increase to describe how the mass of an element changes when it forms a compound.
Percent increase formula
Use this formula to compute percentage growth:
Percent increase = 100 × (final − initial) / |initial|
The |initial| part means you use the absolute value of the starting number (in other words, ignore the minus sign if it’s negative).
Worked example
Say you invested $1,250, and after one year it grew to $1,445. To find the percent increase:
- Write down the initial value (1,250) and the final value (1,445).
- Plug them into the formula.
- Subtract initial from final.
- Divide by the absolute value of the initial amount.
- Multiply by 100.
- If you want, confirm using a Percentage Increase Calculator.
By hand, it looks like this:
[(1,445 − 1,250) / 1,250] × 100
(195 / 1,250) × 100
0.156 × 100
= 15.6% increase
A percentage growth calculator can handle both quick checks and more detailed problems. If you’re working with other percent tasks, a general percentage calculator can help there too.
Calculating percent decrease
Percent decrease works almost the same way, you just switch the order in the subtraction so the result reflects a drop:
Percent decrease = 100 × (initial − final) / |initial|
Example of percent decrease
Using the same investment, assume it was $1,445, and one year later it fell to $1,300. The percent decrease is:
[(1,445 − 1,300) / 1,445] × 100
(145 / 1,445) × 100
0.10 × 100 = 10% decrease
Real-life applications
Percent increase comes up anytime you want to describe growth in a way that’s easy to compare. It often says more than the raw number change because it shows the pace of growth.
Here’s why that matters. Imagine a company reports $1,000,000 more profit than last year. That sounds big, but it doesn’t tell the full story until you know last year’s profit:
- If last year was $1,000,000, then profit rose by 100%, a huge jump.
- If last year was $100,000,000, then profit rose by 1%, which is small.
The relative change (the percentage) gives a clearer picture than the absolute change.
Other everyday examples of percentage increase include:
- Inflation rate, which compares today’s prices to prices 12 months ago
- Salary increase rate, which shows how pay changed year over year (if it beats inflation, buying power often improves)
- Population growth rate, which tracks how fast a region’s population rises
Closely related topics
Sometimes you don’t only want “increase” or “decrease.” You just want the overall change as a percent, no matter the direction. In that case, a percent change or percentage difference calculator may fit better.
These tools are handy for comparing things like average pay across different jobs from one year to the next.
And if you’re comparing measured values to true values, a percent error calculator is the better match.
Where percentage increase is useful
Percentage increase is helpful when you’re tracking change over time or comparing different sets of numbers. It’s often more useful than absolute increase when starting values are different.
For example, moving from 1 to 51 and from 50 to 100 both increase by 50 in absolute terms. But the percent increases are very different:
- 1 to 51 is a 5000% increase
- 50 to 100 is a 100% increase
That’s why percent increase is one of the most common ways to describe growth.
How to calculate percentage increase over time
To find percentage increase per unit of time, follow these steps:
- If you don’t already know the percent change, subtract the initial value from the final value.
- Divide that difference by the absolute value of the initial value.
- Multiply by 100 to get the percentage change.
- Divide that percentage change by the time between the two values.
You now have a rate in % per time (for example, % per second).
- For a straight-line trend, multiply the rate by a time span to estimate change over that span.
- For a curved trend, replace the “final value” with your equation and solve to find change from the start.
How to add a percentage increase to a number
To raise a number by a chosen percent:
- Divide the number by 100 to find 1% of it.
- Multiply that by your percent.
- Add the result back to the original number.
You’ve now added a percentage increase to the value.
How to add 5% to a number
To add 5%:
- Divide the number by 100.
- Multiply the result by 5.
- Add that amount to the original number.
The new value is 105% of the starting value.
How to add two percentages
To add two percentages (as amounts), do this:
- For the first percentage, divide the base number by 100.
- Multiply by the first percent (for example, multiply by 50 for 50%).
- Repeat for the second percentage.
- Add the two results.
If both percentages use the same base number, you can add the percentages first, then calculate the combined percent once.
How to calculate a 10% increase
To add 10% to a number:
- Divide the number by 10, or multiply it by 0.1.
- Add that amount to the original value.
That’s a 10% increase.
How to make a percentage
To find a percentage of a number:
- Start with the number you want a percent of.
- Divide it by 100.
- Multiply by the percent you want.
You’ve now calculated the percentage amount.
What is a 50% increase?
A 50% increase means you add half of the current value to itself. One simple way to do it is to find 50% (half) of the number, then add it back.
Example: 50% of 80 is 40, and 80 + 40 = 120.
This is not the same as a 100% increase, which doubles the original value.
How to calculate percentage increase in Excel
A Percentage Increase Calculator is usually faster, but Excel can do it too:
- Enter the original number in A1.
- Enter the new number in B1.
- In C1, type
=B1-A1, then label it difference. - In D1, type
=(C1/A1)*100, then label it percentage increase. - Right-click the result cell, choose Format Cells.
- Under Number, select Percentage, then pick the decimal places you want.
How to add 20% to a number
To increase a number by 20%:
- Divide the original number by 100 to get 1%.
- Multiply that by 20.
- Add the result to the original number.
That’s the full 20% increase.
