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A Fast Percentage Calculator for Everyday Math

A quick percentage calculator covering the three most common needs: finding what X% of a number is, calculating a percentage increase or decrease between two values, and finding the difference between two numbers.

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Three modes, three different questions

What is X% of Y answers a direct proportion question, like a discount or tip amount. Increase/decrease answers how much something changed relative to where it started. Difference answers how far apart two values are relative to their average, without treating either one as the starting point, useful when comparing two options rather than tracking change over time.

A typical use case

Figuring out a restaurant tip, checking whether a "20% off" sale price is actually correct, or comparing how much a salary changed between two job offers.

Frequently Asked Questions

What's the difference between increase/decrease and difference?

Increase/decrease measures change relative to a starting value. Difference measures the gap between two values relative to their average, with no direction implied.

Can I calculate a discount price with this?

Use What is X% of Y to find the discount amount, then subtract it from the original price yourself.

Does it handle negative numbers?

Yes, all three modes work correctly with negative inputs.

How do I calculate a tip using this?

Use What is X% of Y with the tip percentage as X and the bill amount as Y. The result is the tip to add to your bill.

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