Introduction
The Add Percentage Calculator helps you add or subtract a percent from any number. Type in your number, pick + or −, and enter the percent. You get the answer right away, plus the steps that show how it was found.
This tool has two modes:
- Base + % — add or take away a percent of a number. For example, 200 + 15% = 230.
- % + % — add two percents together. For example, 30% + 45% = 75%.
Use it to add tax or a tip, raise a price, take off a discount, or grow a score. It works with decimals and negative numbers too. A chart shows the base, the change, and the final result, so you can see how the parts fit together. For other percent jobs, try the general Percentage Calculator or the Percentage of Calculator.
How to use our Add Percentage Calculator
Pick a mode, type your numbers, and the calculator shows the answer, the percentage amount, step-by-step math, and a bar chart.
Calculation Mode: Choose "Base + %" to add or subtract a percent from a number. Choose "% + %" to add two percentages together.
Base Value: Type the starting number, like a price or total. Negative numbers are fine.
Operator button (+ or −): Click the middle button to switch between adding the percent and taking it away. If you only ever need one direction, the Percentage Increase Calculator and Percentage Decrease Calculator do the same job.
Percentage Value: Type the percent you want to apply to the base value, such as 15 for 15%.
First Percentage: In "% + %" mode, type the first percent you want to combine.
Second Percentage: In "% + %" mode, type the second percent. The tool adds both and shows the total percent. To average percents instead of adding them, use the Average Percentage Calculator.
Calculate: Results update as you type, but you can click Calculate to refresh them.
Reset to Defaults: Click this to clear your numbers and start over with the sample values.
Adding a Percentage to a Number
Adding a percentage means you take part of a number and then put that part back onto the number. A percent is just a part out of 100. So 15% means 15 out of every 100, or 0.15 as a decimal. If your percent starts as a fraction, the Fraction to Percentage Calculator converts it first.
The Formula
To add a percent to a base value:
- Percent amount = base × (percent ÷ 100)
- Result = base + percent amount
You can also do it in one step: Result = base × (1 + percent ÷ 100)
Example
Add 15% to 200. First, 15 ÷ 100 = 0.15. Then 200 × 0.15 = 30. Last, 200 + 30 = 230. The one-step way gives the same answer: 200 × 1.15 = 230.
Subtracting a Percentage
Taking a percent off works the same way, but you subtract at the end. Take 15% off 200: 200 − 30 = 170. In one step, 200 × 0.85 = 170. For shopping math, the Discount Calculator shows the sale price and the money saved.
Adding Two Percentages Together
When you add two percents that both come from the same base, you can just add the numbers. For example, 30% + 45% = 75%. As a decimal, that is 0.75.
Careful: this only works if both percents are of the same starting number. If one percent is taken after the other changes the number, like a 30% raise followed by a 45% raise, the percents do not simply add. That is called a compound change, and the answer is bigger than 75%. See the Compound Interest Calculator for stacked growth over many periods.
Where You Use This
- Tax: add sales tax to a price with the Sales Tax Calculator, or work backward using the Reverse Sales Tax Calculator.
- Tips: add 18% or 20% to a restaurant bill with the Tip Calculator.
- Sales: take 25% off a sticker price, or set a selling price with the Markup Calculator.
- Pay: add a percent raise to a salary with the Pay Raise Calculator.
- Growth: add a percent increase to sales, weight, or scores, then track it with the Percent Change Calculator.
Common Mistakes
Do not add the percent number straight to the base. Adding 15% to 200 is not 215. You must find 15% of 200 first, which is 30.
Also watch the base. A 10% increase and then a 10% decrease does not bring you back to the start. 100 grows to 110, then drops to 99. The second percent uses a bigger base, so the two changes do not cancel out. To compare two values fairly, the Percent Difference Calculator and Percent Error Calculator use a shared reference instead.