Free Percentage Calculator

Percentages show up everywhere, shopping discounts, tip calculations, test score...

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Format:

What is X% of Y?

What is
%
of=
50

Formula: Result = (Percent / 100) x Number

25% of 200 = (25 / 100) x 200 = 50

Quick Reference: Common Percentages

10% tip

/ 10

15% tip

x 0.15

20% tip

/ 5

25% off

x 0.75

33% off

x 0.67

50% off

/ 2

Double

+100%

Triple

+200%

Quick answer

A percentage calculator works out a percentage of a number, what percent one number is of another, or the percentage increase or decrease between two values. This one runs entirely in your browser and updates the moment you type, showing the full formula for every answer. For example, 15 percent of 200 = (15 / 100) x 200 = 30, and going from 200 to 260 is a 30 percent increase.

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Calculator Features

Percent of Number - What is X% of Y?
What Percent? - X is what % of Y?
Percentage Change - Increase or decrease
Add/Subtract % - Tips and discounts
Formula Display - Learn the math
Quick Reference - Common shortcuts

Why Use Free Percentage Calculator?

4 Calculation Types

Find X% of Y, what percent X is of Y, percentage change between two numbers, and add or subtract percentages from any value.

Instant Results

No calculate button needed. Results appear as you type, so you can try different numbers quickly.

See the Formula

Each calculator shows the actual formula being used, so you can learn and do it yourself next time.

Built-in Tip & Discount

The add/subtract mode works as a tip calculator and discount calculator in one. See both results side by side.

Privacy First

Everything runs in your browser. Your numbers never leave your device.

Works Everywhere

Same great experience on your phone, tablet, or computer. No app download needed.

What Can You Calculate?

Restaurant Tips

Figure out 15%, 18%, or 20% tip on any bill. Split it evenly between friends without awkward math.

Shopping Discounts

See the final price after 20% off, 30% off, or any sale. Know exactly what you'll pay before checkout.

Investment Returns

Calculate percentage gains or losses on stocks, crypto, or any investment. Track your portfolio performance.

Grade Calculations

Convert test scores to percentages. Figure out what you need on the final to get your target grade.

How It Works

1

Pick Your Calculation

Choose what you need: percent of a number, what percent one number is of another, percentage change, or add/subtract a percentage.

2

Enter Your Numbers

Type in your values. The result updates instantly as you change any number.

3

Get Your Answer

See the result immediately. The formula explanation shows you exactly how it was calculated.

Percentage Tips & Tricks

The 10% Shortcut

Finding 10% is easy, just move the decimal one place left. 10% of 847 is 84.7. From there, double it for 20%, halve it for 5%, or multiply by 1.5 for 15%. Master this and you can estimate most tips in your head.

Percentage Changes Aren't Symmetric

A 50% gain followed by a 50% loss doesn't break even, you end up down 25%. Going from 100 to 150 (+50%), then losing 50% brings you to 75. The math only works out if you use the same absolute amount, not the same percentage.

Watch Out for 'Percent Of' vs 'Percent Off'

These sound similar but mean opposite things. 30% of $100 is $30. But 30% off $100 means you pay $70. When shopping, 'percent off' is what you save; you pay 100% minus the discount.

Markup vs. Margin

Retailers often confuse these. A 50% markup on a $20 item means selling for $30. A 50% margin means the $20 cost is 50% of the price, so you sell for $40. Same percentage, very different prices. Ask which one they mean.

Frequently Asked Questions

A percent means a part out of 100, so to find a percentage of a number you multiply by the percent divided by 100. For example, 20% of 150 is 150 x (20 / 100) = 150 x 0.2 = 30. To go the other way and find what percent one number is of another, divide the part by the whole and multiply by 100. Enter your values above and the calculator shows each step.
Divide the part by the whole and multiply by 100. For example, if you scored 45 out of 60 on a test, that's (45 / 60) x 100 = 75%. This works for any situation where you're comparing a smaller number to a larger one, test scores, completion rates, you name it.
For 10%, just move the decimal point one place left. A $47.50 bill has a $4.75 tip at 10%. Double that for 20% ($9.50). For 15%, find 10% and add half of it, $4.75 + $2.38 = $7.13. Our calculator does this math instantly, but knowing the trick helps when you don't have your phone handy.
Take the original price and multiply by (100 - discount) / 100. A shirt marked $80 with 25% off: $80 x 0.75 = $60. Or do it in two steps: find 25% of $80 ($20) and subtract it. Either way, you're paying $60. Our add/subtract calculator shows both the discounted price and how much you're saving.
Because you're dividing by different starting numbers. Going from 100 to 125 is a 25% increase (25 / 100). But going from 125 back to 100 is only a 20% decrease (25 / 125). This trips people up all the time. A 50% drop followed by a 50% gain doesn't get you back to where you started, you end up 25% lower.
You can't divide by zero, it's mathematically undefined. If you're asking what percent 50 is of 0, there's no meaningful answer because you can't have parts of nothing. Our calculator shows 'Undefined' in these cases instead of giving you a misleading number.
Subtract the old value from the new value, divide by the old value, and multiply by 100. If your rent went from $1,200 to $1,350, that's ($1,350 - $1,200) / $1,200 x 100 = 12.5% increase. For decreases, you'll get a negative number, a drop from $1,350 to $1,200 is -11.1%.
Multiply the number by X divided by 100. So 15% of 240 is 240 x (15 / 100) = 240 x 0.15 = 36. You can also think of it as moving the decimal two places left on the percentage, then multiplying. 15% becomes 0.15.
Multiply the price by (1 + tax rate / 100). If sales tax is 8.25%, a $50 item costs $50 x 1.0825 = $54.13 after tax. This is the same as finding 8.25% of $50 ($4.13) and adding it. Our calculator shows both the final price and the tax amount.
Percent is relative, percentage points are absolute. If a rate goes from 5% to 10%, it increased by 5 percentage points but doubled (100% increase). News headlines often mix these up. 'Unemployment rose 2%' and 'Unemployment rose 2 percentage points' mean very different things if unemployment was at 4%.
Divide the sale price by (100 - discount) / 100. If something costs $60 after a 25% discount, the original was $60 / 0.75 = $80. You can check: 25% of $80 is $20, and $80 - $20 = $60. This works for figuring out pre-tax prices too.
Yes, but you need to apply them one at a time. A 10% increase followed by a 20% increase isn't 30%, it's 32%. Start with 100, add 10% to get 110, then add 20% of 110 (22) to get 132. That's why compound interest grows faster than simple interest.
Very accurate, it uses standard floating-point math and displays up to 10 decimal places when needed. For everyday calculations like tips and discounts, you'll get the same results as any financial calculator. Just remember that real-world prices get rounded to the nearest cent.

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