Percentage Increase or Decrease Calculator: Find New Values Easily
ByMuhammad Ali•Founder of KruskalCode
21:02
6 min read
Percentages are fundamental in many aspects of life, from understanding financial reports to calculating discounts and sales tax. Knowing how to calculate a new value after a percentage increase or decrease is a crucial skill. This guide will walk you through the concepts, formulas, and practical applications, complemented by our easy-to-use online calculator.
Explanation
A percentage increase means a value has grown by a certain proportion of its original amount. Conversely, a percentage decrease means a value has shrunk. These calculations are vital for tracking growth, understanding price changes, or analyzing data. For example, if a product's price goes up by 15%, you'll want to know the new price. Similarly, if a store offers a 25% discount, you'll need to find the final cost.
Formula
To calculate a new value after a percentage change, use these formulas: For Percentage Increase: New Value = Original Value + (Original Value × Percentage / 100) For Percentage Decrease: New Value = Original Value - (Original Value × Percentage / 100) In both cases, the 'Percentage' should be entered as a whole number (e.g., 20 for 20%).
Example
Let's say you have an investment worth $1,200. If it experiences a 5% increase, the calculation would be: New Value = $1,200 + ($1,200 × 5 / 100) = $1,200 + $60 = $1,260. If, however, the investment decreased by 5%, the calculation would be: New Value = $1,200 - ($1,200 × 5 / 100) = $1,200 - $60 = $1,140. This demonstrates how a small percentage can lead to significant changes in value.
How to use the related calculator
Using our Percentage Increase or Decrease Calculator is straightforward. First, enter the 'Original Value'—this is the starting number you want to modify. Next, input the 'Percentage Change' as a whole number (e.g., '15' for 15%). Finally, select whether you want to 'Increase By' or 'Decrease By' using the dropdown menu. The calculator will instantly display the new value, along with the calculated change amount.
Try the related calculator
Open toolFAQ
What is the difference between percentage change and percentage increase/decrease?
Percentage change typically refers to the overall percentage difference between two values, often without specifying direction. Percentage increase/decrease specifically calculates the new value after applying a known percentage growth or reduction to an initial value.
Can I use this calculator for discounts and sales tax?
Absolutely! For discounts, select 'Decrease By' and enter the discount percentage. For sales tax, select 'Increase By' and enter the tax rate percentage to find the total price including tax.
What if the percentage decrease is larger than the original value?
If the percentage decrease is so large that it would result in a negative value (e.g., decreasing 100 by 120%), our calculator will alert you that the decrease is too large, as a value cannot typically go below zero in this context.
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About the author
Muhammad Ali. Muhammad Ali is a full-stack developer and founder of KruskalCode. He builds SaaS platforms and automation systems with React and Laravel, and helps teams ship fast, scalable tools.
Need a custom calculator, dashboard, or automation workflow? Reach out to KruskalCode.
