Solve any percentage calculation — from "what is X% of Y" to percentage increase or decrease.
Percentage calculations show up constantly in everyday life — figuring out a discount at checkout, calculating a tip, working out what portion of a budget was spent, or understanding how much a price has gone up or down. Despite being common, percentage math is a frequent source of small errors when done by hand or in your head, particularly for the "percentage change" calculation, which trips people up because it requires dividing by the original (starting) value, not the new one.
This tool covers the three percentage calculations people need most often, each as its own tab so there's no ambiguity about which formula is being applied. "X% of Y" answers questions like "what is 20% of 150" — the classic discount or tip calculation. "X is what % of Y" flips that around, answering "30 is what percent of 150" — useful for figuring out what portion one number represents of a whole. "Percentage change from X to Y" calculates the percentage increase or decrease between an original and a new value, correctly using the original value as the base of the calculation, which is where manual percentage-change math most often goes wrong.
It's used for retail discount and markup calculations, financial analysis of price or metric changes over time, students working through percentage-based homework, and anyone needing a fast, reliably correct percentage answer without re-deriving the formula from memory each time.