Why Everyone Needs This Tool
Percentages are everywhere—from the tip on your dinner bill to the battery life on your phone. Yet, our brains often freeze up when trying to calculate them on the spot. This tool is your digital cheat sheet.
Real-World Examples
- Shopping: A shirt is $40 with a 15% discount. Select "Subtract Percentage" to see you'll pay $34.
- Tipping: Your bill is $56.50 and you want to leave 20%. Select "What is X% of Y?" to find the tip amount ($11.30).
- Business Growth: Revenue went from $100k to $150k. Select "Percentage Increase" to show your boss a 50% growth stat!
The "Percent of Percent" Trap
Be careful with stacked percentages. If a stock drops 50% and then gains 50%, you are NOT
back to even. You are actually down 25%!
Example: $100 drops to $50. $50 grows by
50% ($25) to become $75.
Frequently Asked Questions
This is used when comparing two values where neither is "original" (like the height of two buildings). It divides the difference by the average of the two numbers.
Yes! Use mode #12. Remember, Margin is based on revenue, while Markup is based on cost. They are often confused but give very different numbers.