Last updated: March 2026
How to Calculate Percentages
Percentages are everywhere: sales tax, tip calculations, exam scores, investment returns, discounts, statistics. Despite being fundamental, many people struggle to calculate them quickly in their heads. This calculator handles nine different percentage calculations instantly.
Percentage calculations are among the most common math operations in everyday life, from calculating tips and discounts to understanding statistics and financial returns.
Percent of a number is the most common calculation. "What is 20% of 150?" Divide 20 by 100 (= 0.2) and multiply by 150 (= 30). Percentage change tells you how much something increased or decreased — useful for stock prices, salary raises, and price changes.
For business, markup and margin are crucial but often confused. Markup is profit as a percentage of cost. Margin is profit as a percentage of revenue. A product that costs $50 and sells for $75 has a 50% markup but a 33.3% margin. Both are valid — just different reference points.
The discount calculator handles stacked discounts, which catch many people off guard. A 25% discount followed by a 10% discount is NOT 35% off — it's 32.5% off. The second discount applies to the already-reduced price, not the original.
Frequently Asked Questions
How do I calculate a percentage of a number?
Divide the percentage by 100, then multiply by the number. For example, 15% of 200 = (15/100) × 200 = 30. Our calculator does this instantly as you type.
What's the difference between percentage change and percentage difference?
Percentage change measures how much a value changed relative to the original value (from 200 to 250 = +25%). Percentage difference compares two values using their average as the base (200 vs 250 = 22.22%).
What's the difference between markup and margin?
Markup is profit divided by cost. Margin is profit divided by revenue. A 50% markup equals a 33.3% margin on the same transaction. Markup is always higher than margin for the same profit.
How do stacked discounts work?
Stacked discounts are NOT additive. 25% off then 10% off does NOT equal 35% off. The second discount applies to the already-reduced price. 25% + 10% stacked = 32.5% effective discount.
Is this calculator free?
Yes, completely free. No signup, no limits, no ads. All calculations happen in your browser.
Can I use this for business calculations?
Absolutely. The markup, margin, and discount calculators are designed for business use. Calculate selling prices, profit margins, and sale discounts instantly.