Percentages are everywhere — discounts, taxes, tips, interest, statistics, grade curves — yet the three classic questions are easy to mix up: What is 15% of 80? 12 is what percent of 60? What is the change from 50 to 65? Each needs a different formula, and reaching for the right one under time pressure is where mistakes happen.
This calculator answers all three forms instantly, plus percentage increase and decrease. Type the numbers, read the result — with the formula shown so you understand what was computed.
How to Use This Tool
- Pick the question type: X% of Y, X is what % of Y, or % change from X to Y.
- Enter your two numbers.
- The result appears instantly with the underlying formula.
- Use the % change mode for price increases, growth rates, and statistics.
Frequently Asked Questions
What is the difference between percentage and percentage points?
If a rate moves from 10% to 15%, it rose 5 percentage points but 50 percent (the increase relative to the starting 10%). News reports and financial documents mix these up constantly — the distinction matters enormously for interest rates and statistics.
How do I calculate a price after a discount?
Multiply the price by (100 − discount)/100: a $80 item at 25% off is 80 × 0.75 = $60. For successive discounts, apply them one at a time — 20% then 10% off is 28% total, not 30%.
How is percentage change calculated?
(new − old) / old × 100. From 50 to 65: (65−50)/50 × 100 = +30%. Note the asymmetry: a 50% drop needs a 100% rise to recover, which is why sequential gains and losses do not simply cancel.