KLOORAHow to Calculate Percentage Increase and Decrease
Published 6 November 2026 by Kloora Tools
Quick answer: use the free Percentage Increase and Decrease Calculator to calculate the percentage change between an old and a new value. It runs in your browser, so nothing you enter is uploaded or stored, and there is no signup.
What is the Percentage Increase and Decrease Calculator?
Calculate the percentage change between an old and a new value. People often search for it as "percentage increase calculator", "percentage decrease calculator" or "percent change calculator". This free version works on any phone or computer and needs no download.
How to use the Percentage Increase and Decrease Calculator
- Open the Percentage Increase and Decrease Calculator.
- Enter your values in the fields.
- The results update instantly as you type.
- Note or copy the numbers you need.
How it works
Percent change = (new - old) / old x 100. A positive result is an increase and a negative result is a decrease. Note that a 50 percent increase followed by a 50 percent decrease does not return to the start, because the second percentage is taken from a bigger number.
Worked example
- Input: Old value: 80; New value: 100
- Result: Increase: 25%; Difference: 20; As a ratio: 1.25 x
Common uses
- Measure price rises and salary raises
- Compare sales or traffic between two months
- Check a discount or a change in a score
Second worked example
Here is the same tool with larger numbers, so you can see how the result scales.
- Input: Old value: 120; New value: 150
- Result: Increase: 25%; Difference: 30; As a ratio: 1.25 x
Tips for the best result
- Check the units and the order of the numbers before you press anything.
- Estimate the answer roughly in your head first, so you can spot an input mistake.
- Keep more decimal places during the work and round only the final answer.
- Try a simple case you already know to confirm the tool does what you expect.
Common mistakes to avoid
- Swapping two inputs, such as base and exponent or x and y.
- Using degrees where radians are expected, or the other way round.
- Rounding too early and carrying the error forward.
- Entering a percentage as a decimal, or a decimal as a percentage.
Percentage Increase and Decrease Calculator compared with doing it by hand
| Percentage Increase and Decrease Calculator | By hand or in a spreadsheet | |
|---|---|---|
| Speed | Instant, results update as you type | Slow, you rebuild the steps each time |
| Accuracy | Same standard method every time | Easy to slip on a formula or a unit |
| Privacy | Runs in your browser, nothing uploaded | Depends on the software you use |
| Cost | Free, no signup | Free or paid software needed |
Try it now
Open the Percentage Increase and Decrease Calculator and try your own numbers or text. If it helps, share it with someone who needs it.
Frequently asked questions
What is the percentage increase formula?
(new value - old value) / old value x 100.
What if the result is negative?
A negative result is a percentage decrease.
What does the Percentage Increase and Decrease Calculator do?
Calculate the percentage change between an old and a new value.
How do I use the Percentage Increase and Decrease Calculator?
1. Enter your values in the fields. 2. The results update instantly as you type. 3. Note or copy the numbers you need.
Is my data safe when I use the Percentage Increase and Decrease Calculator?
Yes. Everything runs in your browser on your own device. Nothing you type or choose is uploaded, stored or shared, and no AI service is used.
Does the Percentage Increase and Decrease Calculator work on a phone?
Yes. It works on phones, tablets and computers in any modern browser, with nothing to install.
Do I need an account or a payment to use the Percentage Increase and Decrease Calculator?
No. It is free, has no daily limit, no watermark and needs no signup.
What information does the Percentage Increase and Decrease Calculator need?
You enter: Old value, New value. The results update instantly as you change any value.
How does the Percentage Increase and Decrease Calculator work?
Percent change = (new - old) / old x 100.
Can I use this for "percentage decrease calculator"?
Yes. The Percentage Increase and Decrease Calculator is built for exactly that, and it also answers searches such as "percentage increase calculator" and "percent change calculator".
How accurate is the Percentage Increase and Decrease Calculator?
It uses the standard method and shows results to a sensible precision. For legal, medical, financial or safety decisions, confirm important numbers with a qualified professional.
Where can I find more free tools like the Percentage Increase and Decrease Calculator?
Kloora Tools has over 150 free tools for CVs, PDFs, images, Urdu, calculators and everyday tasks. Browse them all from the home page.
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