Whether you’re trying to figure out a sale discount, calculate a tip at a restaurant, understand a pay raise, or check your test score — our free Percentage Calculator handles it all instantly. No formulas to memorize. No math required. Just enter your numbers and go.
What Can This Percentage Calculator Do?
Our tool covers every common percentage problem you’ll encounter in everyday life:
1. What is X% of Y? Find a percentage of any number. Example: What is 20% of 250? → 50
2. X is what percent of Y? Find out what percentage one number represents of another. Example: 40 is what percent of 200? → 20%
3. X is Y% of what number? Work backward from a percentage result. Example: 30 is 15% of what? → 200
4. Percentage Difference Find the percentage difference between two values. Example: What is the percentage difference between 80 and 100? → 22.22%
5. Percentage Change (Increase or Decrease) Calculate how much something went up or down in percentage terms. Example: A price went from $40 to $52 — that’s a 30% increase.
How to Use the Calculator
It’s completely straightforward:
- Pick the type of percentage problem you want to solve from the options above.
- Enter your known values in the input fields.
- Hit Calculate — your answer appears instantly with the full breakdown.
No sign-up. No ads. No nonsense. Completely free.
What Is a Percentage?
A percentage is simply a way of expressing a number as a fraction of 100. The word “percent” comes from the Latin per centum, which literally means “by the hundred.” So when someone says “25%,” they mean 25 out of every 100 — or one quarter of the whole.
Percentages are everywhere in daily American life:
- Sales tax in the U.S. averages around 7.12%
- Tipping at restaurants is typically 15%–20%
- Interest rates on savings accounts, mortgages, and credit cards
- Test scores — 85% means you got 85 out of 100 questions right
- Discounts — “30% off” means you pay only 70% of the original price
The Percentage Formula (Explained Simply)
The basic percentage formula is:
Percentage (P) × Base Value (V1) = Result (V2)
Or rearranged:
P = (V2 ÷ V1) × 100
Example 1 — What is 35% of 80?
P × V1 = V2 0.35 × 80 = 28
Answer: 35% of 80 is 28.
Example 2 — 15 is what percent of 60?
P = (15 ÷ 60) × 100 = 25%
Answer: 15 is 25% of 60.
Example 3 — 45 is 90% of what number?
V1 = V2 ÷ P = 45 ÷ 0.90 = 50
Answer: 45 is 90% of 50.
Percentage Difference vs. Percentage Change — What’s the Difference?
These two are commonly confused, but they are not the same thing.
| Concept | What It Measures | Formula | Example |
|---|---|---|---|
| Percentage Difference | The relative difference between two values (no direction) | |V1−V2| ÷ ((V1+V2)/2) × 100 | 80 vs 100 → 22.22% |
| Percentage Change | How much one value changed relative to a starting value | (New−Old) ÷ Old × 100 | $50 → $65 = 30% increase |
When to use which:
- Use percentage difference when comparing two values without a clear “before” and “after” (e.g., comparing two test scores from different tests).
- Use percentage change when you have a starting point and an ending point (e.g., a stock price that went from $120 to $144 — that’s a 20% increase).
How to Calculate Percentage Increase and Decrease
Percentage Increase Formula:
% Increase = ((New Value − Old Value) ÷ Old Value) × 100
Example: Your monthly rent went from $1,200 to $1,380. % Increase = ((1,380 − 1,200) ÷ 1,200) × 100 = 15%
Percentage Decrease Formula:
% Decrease = ((Old Value − New Value) ÷ Old Value) × 100
Example: A TV originally priced at $650 is now on sale for $520. % Decrease = ((650 − 520) ÷ 650) × 100 = 20%
Real-Life Percentage Examples Every American Deals With
💰 Shopping Discounts
That jacket is marked “40% off” its $85 original price. How much do you save? 40% of $85 = $34 in savings → You pay $51.
🍽️ Restaurant Tips
Your dinner bill is $62.50 and you want to tip 18%. 18% of $62.50 = $11.25 → Total with tip: $73.75
📊 Salary Raise
You currently earn $55,000/year and you’re getting a 6% raise. 6% of $55,000 = $3,300 → New salary: $58,300
🏦 Sales Tax
You’re buying a laptop for $999 and your state has 8.5% sales tax. 8.5% of $999 = $84.92 → Total cost: $1,083.92
📝 Test Scores
You got 47 out of 55 questions correct on a quiz. What’s your score? (47 ÷ 55) × 100 = 85.45%
📈 Investment Returns
You invested $5,000 and it’s now worth $6,250. What’s your return? ((6,250 − 5,000) ÷ 5,000) × 100 = 25% return
Percentage Quick Reference Table
| Percent | Decimal | Fraction |
|---|---|---|
| 1% | 0.01 | 1/100 |
| 5% | 0.05 | 1/20 |
| 10% | 0.10 | 1/10 |
| 12.5% | 0.125 | 1/8 |
| 20% | 0.20 | 1/5 |
| 25% | 0.25 | 1/4 |
| 33.33% | 0.3333 | 1/3 |
| 50% | 0.50 | 1/2 |
| 66.67% | 0.6667 | 2/3 |
| 75% | 0.75 | 3/4 |
| 100% | 1.00 | 1/1 |
How to Calculate Percentage in Your Head (Mental Math Tips)
You don’t always have a calculator handy. Here are some quick tricks used by Americans every day:
The 10% Trick: Move the decimal point one place to the left. 10% of $85 = $8.50
The 1% Trick: Move the decimal two places to the left. 1% of $240 = $2.40
Build Up From There: 20% = double the 10% amount → 10% of $60 = $6, so 20% = $12 15% tip = 10% + 5% (half of 10%) → 10% of $50 = $5, 5% = $2.50, so 15% = $7.50
The Reversal Trick: X% of Y = Y% of X. So 8% of 50 = 50% of 8 = 4. This can make mental math much easier.
How to Convert Between Percentages, Decimals, and Fractions
Percent → Decimal: Divide by 100 75% → 75 ÷ 100 = 0.75
Decimal → Percent: Multiply by 100 0.43 → 0.43 × 100 = 43%
Percent → Fraction: Write over 100 and simplify 60% → 60/100 → simplified = 3/5
Fraction → Percent: Divide numerator by denominator, then × 100 3/8 → 3 ÷ 8 = 0.375 → × 100 = 37.5%
Percentage in Finance: What You Should Know
Percentages are at the core of almost every financial decision Americans make:
Annual Percentage Rate (APR) is used for credit cards and loans. A card with 24% APR charges 2% per month in interest on your balance.
Annual Percentage Yield (APY) is used for savings accounts and reflects compound interest — it’s usually slightly higher than APR.
Down Payment Percentage — Most US mortgage lenders require at least 3–20% of the home’s price as a down payment.
401(k) Contribution — Many employers match employee contributions up to a certain percentage. If your employer matches 50% of your contributions up to 6% of your salary, you’d want to contribute at least 6% to get the full match.
Understanding these percentages can save — or cost — you thousands of dollars.
Frequently Asked Questions (FAQ)
How do I calculate 20% of a number?
Multiply the number by 0.20, or simply find 10% (move the decimal one place left) and double it. For example, 20% of 350: 10% = 35, doubled = 70.
What is the percentage formula?
The basic formula is: Percentage = (Part ÷ Whole) × 100. For example, if you got 42 out of 50 on a test: (42 ÷ 50) × 100 = 84%.
How is percentage difference different from percentage change?
Percentage change requires a defined starting point and direction (increase or decrease). Percentage difference is symmetric — it doesn’t matter which value comes first. Use percentage change when tracking progress over time; use percentage difference when comparing two unrelated values.
How do I calculate a percentage discount?
Use the formula: Discount % = ((Original Price − Sale Price) ÷ Original Price) × 100. If a jacket was $120 and is now $84: ((120−84) ÷ 120) × 100 = 30% off.
What is 15% of 200?
15% of 200 = 0.15 × 200 = 30. Or: 10% of 200 = 20, 5% = 10, so 15% = 30.
How do I figure out what percentage one number is of another?
Divide the smaller number by the larger one, then multiply by 100. For example, 18 is what percent of 72? (18 ÷ 72) × 100 = 25%.
How do you calculate a tip percentage?
Multiply your bill total by the tip percentage in decimal form. For an 18% tip on a $55 bill: 55 × 0.18 = $9.90. Round up to $10 for convenience.
What is 100 percent of any number?
100% of any number is simply that number itself. 100% means “the whole thing” — so 100% of 75 is 75.
Related Calculators You’ll Find Useful
- Fraction Calculator — Convert between fractions, decimals, and percentages
- Mortgage Calculator — Understand your down payment and interest rate percentages
- Compound Interest Calculator — See how interest rates grow your savings over time
- GPA Calculator — Convert letter grades and understand your grade average
- Tip Calculator — Instantly calculate restaurant tips without mental math
This Percentage Calculator is for educational and everyday use. For tax, financial, or legal calculations, always verify with a licensed professional.