Percentage Calculator

A percentage calculator answers the most common question in everyday math: what is X% of Y? "Percent" literally means "per hundred" — so 25% means 25 out of every 100. This calculator handles that and the related problems people search for most: percentage increase, percentage decrease, and figuring out what percentage one number is of another.

Percentages show up everywhere — sales tax, restaurant tips, stock returns, test scores, sale prices, interest rates, body fat percentage, weather forecasts. Knowing how to compute them in your head saves real money in real situations.

Sales tax example: A laptop costs $1,200 and sales tax is 8.25%.

• Tax = (8.25 ÷ 100) × 1,200 = $99
• Total = 1,200 + 99 = $1,299

Tip example: A meal costs $58 and you want to leave 18%.

• Tip = 0.18 × 58 = $10.44

Discount example: A jacket is on sale for 30% off $89.

• Discount = 0.30 × 89 = $26.70
• Sale price = 89 − 26.70 = $62.30
• Shortcut: pay 70% of original = 0.70 × 89 = $62.30

• Shopping — comparing discounts and figuring out the actual sale price.
• Tipping and tax — quick mental math at the restaurant or checkout.
• Investing — calculating returns and percentage changes between two prices.
• Grading and scoring — converting raw scores into percentages for school or work.
• Cooking — scaling recipes up or down by a percentage.
• Comparing options — figuring out which deal is actually better when discounts are stacked.

• Adding then subtracting the same percent. Going up 10% and then down 10% does not return you to the start — you end up about 1% lower because the bases differ.
• Confusing percent with percentage points. A rate going from 4% to 6% is a 2-point increase but a 50% relative jump.
• Stacking discounts wrongly. "30% off plus an extra 20% off" is not 50% off — it's 44% off, because the 20% applies to the already-discounted price.
• Forgetting to convert. When using a calculator, 25% in formulas should be 0.25, not 25 — unless your formula already divides by 100.
• Misreading negative changes. A −20% and a +25% don't cancel out: dropping from 100 to 80, then up 25% returns to 100. But a −50% requires +100% to recover.