Percentage Calculator

Percentages Are Everywhere — And They Trip People Up Constantly

Discounts. Tax. Tips. Interest rates. Grade percentages. Survey results. Nutritional information. Percentage change year over year. Percentages show up in nearly every area of everyday life — and most of us learned to calculate them in school, then immediately forgot exactly how.

This calculator handles the math instantly so you can get to the answer without the mental gymnastics.

The Four Percentage Calculations You'll Actually Use

1. What is X% of Y? Example: What is 15% of $85? (for calculating a tip) → Answer: $12.75

2. X is what percent of Y? Example: 42 is what percent of 200? (for understanding a score or ratio) → Answer: 21%

3. Percentage increase Example: A product went from $80 to $96. What's the percentage increase? → Answer: 20%

4. Percentage decrease Example: A price dropped from $120 to $90. What's the percentage decrease? → Answer: 25%

This tool handles all four with clearly labeled inputs — no guessing which formula applies.

Real-World Uses for This Tool

• Shopping: Calculate the actual discount on a "30% off" sale, or figure out the final price after tax.

• Finance: Understand how much of your salary goes to various expenses, or calculate returns on an investment.

• School/Study: Quickly convert scores to percentages or figure out what grade you need on a final exam.

• Work: Calculate percentage change in KPIs, revenue growth, conversion rate changes, or survey responses.

• Fitness: Track percentage changes in weight, reps, or performance metrics.

• Cooking: Scale recipes up or down by a percentage.

Common Percentage Mistakes (and How to Avoid Them)

Confusing "50% more" with "50% of" "50% more than 100" is 150. "50% of 100" is 50. They sound similar but mean very different things.

Percentage change vs. percentage point change If a rate goes from 10% to 15%, that's a 5 percentage point increase but a 50% percentage change. The distinction matters enormously in data reporting.

Reversing a percentage discount incorrectly If something is discounted 20% to $80, the original price wasn't $96 — it was $100. Adding 20% back to the discounted price gives the wrong answer.

How to Use the Tool

1. Choose your calculation type from the four options.

2. Enter your numbers.

3. Get your instant result.

No formulas to remember. No mental arithmetic. Just the answer.

FAQ

What's the formula for percentage? The basic formula is: Percentage = (Part ÷ Whole) × 100

How do I calculate percentage change? ((New Value - Old Value) ÷ Old Value) × 100. Positive = increase, negative = decrease.

Can I calculate reverse percentages? Yes — use the "X is what percent of Y" mode, or calculate what the original value was before a percentage was applied.

Is percentage the same as "per cent"? Yes — "percent" literally means "per hundred." 25% = 25 per 100 = 0.25.