TetraKits
The TetraKits Percentage Change Calculator runs entirely in your browser — free, private, and ready on mobile or desktop.
Overview
Sales reports, investment returns, and grade improvements all ask "what percent did this change?" — but the ((new − old) ÷ old) × 100 formula is easy to invert. Enter both values and read the answer instantly.
How to use the percentage change calculator
Enter an original value and a new value to calculate percent change — see whether it is an increase or decrease, the percentage, and the absolute difference instantly.
Common use cases
Enter an original value and a new value to calculate percent change — see whether it is an increase or decrease, the percentage, and the absolute difference instantly. Bookmark the tool for quick access during projects.
FAQ
What if the original value is zero?
Percent change from zero is undefined (division by zero). Enter a non-zero original value.
Is a drop shown as negative?
Yes. Decreases show negative percent change — e.g. 100 → 80 = −20%.
How is this different from percentage calculator?
This tool compares two values over time. The percentage calculator handles "X% of Y" and other modes.
Can I use this for stock returns?
Yes. Enter purchase price as original and current price as new for percent gain or loss.
Is this percentage change calculator free?
Yes. Unlimited calculations with no signup.
