Percentage Calculators - Help & Documentation
Master our percentage tools quickly with this easy-to-follow guide.
Quick Start & Requirements
- JavaScript Required
Just Percent runs entirely in your browser. Just make sure JavaScript is enabled to get started.
- Decimal Separators
Use the decimal separator that matches your locale settings. For example:
- In locales that use a dot (.), write numbers like 10.5.
- In locales that use a comma (,), write numbers like 10,5.
- Thousands Separator
Thousands separators are ignored when you type. You don't need to include them. The app uses your locale settings to interpret pasted numbers correctly. For example, "1,000" is read as one thousand in dot-decimal locales (where comma is the thousands separator) but as one in comma-decimal locales (where comma is the decimal separator). Similarly, "1.000" is read as one thousand in comma-decimal locales but as one in dot-decimal locales.
- Instant Results
Calculations happen in real-time as you type. No need to hunt for a "Calculate" button.
Helpful Calculator Features
Our calculators include several features to make your calculations faster and easier:
Smart Clipboard
- Paste numbers instantly with the Paste button (Chrome only, after allowing clipboard access when prompted).
- Click Add to Memos to copy the result to your clipboard and save it to your memos list.
- Results are copied as plain numbers (no currency symbols, percent signs, or formatting), so they paste cleanly into any app.
Keyboard Shortcuts
- Enter moves to the next field, or when pressed in the last field, saves to memos, copies the result to clipboard, and returns focus to the first field.
- Escape clears everything for a fresh start.
- Space jumps between fields.
Drag-to-Adjust Values
- Click and hold any number field, then drag left or right to adjust the value.
- Power user tip! Hold Alt (or Option) for larger jumps, or Shift for whole numbers.
Calculation Memos
- The current calculation is saved when you press Enter in the last field or click the Add to Memos button.
- Clicking any previous entry reloads it instantly.
- Single items can be cleared, or you can wipe the slate clean with one click.
- Your data stays private - everything is stored right in your browser.
- We keep your last 20 calculations, automatically making room for new ones.
Customize Your Layout
- Drag and drop calculator cards to rearrange them.
- Put your favorites at the top for quick access.
- Your layout is saved automatically.
Collapse Calculator Sections
- Hover over the top edge of any calculator card to reveal chevron controls (↑ ↓).
- Use the chevrons to progressively hide or show sections like memos, hints, or the input form.
- The system automatically skips levels that have no effect in your current view.
- Your visibility preferences are saved per calculator and restored on your next visit.
- On touch devices, the chevron controls are always visible.
Mobile-Friendly
- Works perfectly on phones, tablets, and desktops.
- Touch-friendly buttons and clear navigation.
Extras
- One-click Dark Mode.
- Visual formulas to help you understand the math.
- Smart validation ensuring precise results every time.
Basic Percentage CALCULATOR
Calculate the percentage value of a given number.
Practical Uses
- Daily Nutritional Value:
40% [X] of a standard 2,000 [Y] calorie diet is how many calories [Z]?
800 calories - Grade Points:
Scoring 85% [X] on a 120 [Y] point exam earns how many points [Z]?
102 points - Investment Interest:
5% [X] APR on a $1,000 [Y] high-yield savings account earns how much [Z]?
$50 - Restaurant Tip:
A 15% [X] tip on a $60 [Y] restaurant bill comes to how much [Z]?
$9 - Sale Discount:
20% [X] off a $80 [Y] pair of jeans saves you how much [Z]?
$16 - Tax Calculation:
8% [X] tax on a $250 [Y] pair of wireless earbuds comes to how much [Z]?
$20
How to Use
- Enter the percentage in the first box.
- Enter the total number in the second box.
- The result appears instantly in the third box.
- Check "Round" if you want to keep the result to two decimal places.
- Save it to Memos with Enter or the "Add to Memos" button.
How It Works
The Basic Percentage calculator uses this formula:
Example: What is 20% of 80?
So 20% of 80 is 16.
Original Value CALCULATOR
The Original Value calculator (also known as reverse percentage calculator) helps you find the original value when you know a percentage and its result. This is useful for working backward from a known percentage to find the original amount.
Practical Uses
- Pre-Discount Price:
25% [X] of what original price [Y] is a $50 [Z] discount on a smartwatch?
$200 - Pre-Tax Amount:
8% [X] of what pre-tax amount [Y] is $16 [Z] tax?
$200 - Original Value:
15% [X] of what dinner bill [Y] is a 30 [Z] tip?
200 - Pre-Increase Salary:
10% [X] of what original base salary [Y] is a $5,000 [Z] salary increase?
$50,000 - Investment Principal:
12% [X] of what original seed capital [Y] is a $2,400 [Z] return?
$20,000 - Total Budget:
30% [X] of what total Christmas budget [Y] is $600 [Z]?
$2,000
How to Use
- Enter the percentage in the first box.
- Enter the part value in the third box.
- The original value appears instantly in the middle box.
- Check "Round" if you want to keep the result to two decimal places.
- Save it to Memos with Enter or the "Add to Memos" button.
How It Works
The Original Value calculator uses this formula:
Example: If 15% equals 30, the original value is:
So the original value is 200.
Important Note
When the percentage is 0%, the calculation is undefined because you cannot divide by zero.
Part-to-Whole Percentage CALCULATOR
Find what percentage one number is of another.
Practical Uses
- Goal Conversion Rate:
What is the conversion rate [X%] for a football (soccer) player with 100 [Y] shots and 30 [Z] goals?
30% - Rent Share:
What percentage [X%] of your $4,000 [Y] monthly income goes to $800 [Z] rent in a city?
20% - Market Share:
What is an electric car maker's market share [X%] if total EV sales are $1,000,000 [Y] and the company sells $250,000 [Z]?
25% - Savings Progress:
What percentage [X%] of your $10,000 [Y] emergency fund have you reached with $7,500 [Z] saved?
75% - Task Completion:
What percentage [X%] of 24 [Y] weekly chores is 18 [Z] completed tasks?
75% - Test Score:
What is your grade [X%] on a 100 [Y] point licensing exam section when scoring 85 [Z] points?
85%
How to Use
- Enter the whole value in the middle box.
- Enter the part value in the third box.
- The percentage result appears instantly in the first box.
- Check "Round" if you want to keep the result to two decimal places.
- Save it to Memos with Enter or the "Add to Memos" button.
How It Works
The Part-to-Whole Percentage calculator uses this formula:
For example, to find what percentage 25 is of 100, the calculator computes:
So 25 is 25% of 100.
Important Note
When the whole/total value is 0, the percentage is undefined because you cannot divide by zero.
Percentage Change CALCULATOR
Calculate the percentage difference between two values to determine increases or decreases.
Practical Uses
- Inflation Rate:
A concert ticket rising from $100 [Original] to $103 [New] represents what inflation rate [Change%]?
3% - Performance Improvement:
Monthly sales leads improving from 70 [Original] to 84 [New] represents what percentage improvement [Change%]?
20% - Revenue Growth:
Small business revenue growing from $1,000,000 [Original] to $1,200,000 [New] represents what percentage growth [Change%]?
20% - Salary Change:
A local retailer manager's salary increase from $50,000 [Original] to $54,000 [New] represents what percentage salary increase [Change%]?
8% - Stock Price Change:
a streaming company stock going from $50 [Original] to $75 [New] represents what percentage change [Change%]?
50% increase - Website Traffic Change:
A drop in online shop visits from 10,000 [Original] to 8,500 [New] represents what percentage change [Change%]?
15% decrease - Weight Loss:
Weight dropping from 80 [Original] kg to 72 [New] kg on a new diet plan represents what percentage change [Change%]?
10% decrease
How to Use
- Enter the original value in the first box.
- Enter the new value in the second box.
- The percentage change appears instantly.
- A negative result means the value decreased.
- Save it to Memos with Enter or the "Add to Memos" button.
How It Works
The Percentage Change calculator uses this formula:
Example: What is the percentage change from 50 to 75?
The value increased by 50%.
Increased Value CALCULATOR
See what you get after boosting a value by the Increase %.
Practical Uses
- Budget Boost:
A $5,000 [Original] family trip budget increased by 25% [Increase] becomes what [New]?
$6,250 - Investment Growth:
A $2,000 [Original] retirement account growing by 12% [Increase] becomes what [New]?
$2,240 - Population Growth:
A city of 100,000 [Original] people with 3% [Increase] growth reaches what population [New]?
103,000 - Price Inflation:
A $120 [Original] grocery bill with 5% [Increase] inflation becomes what [New]?
$126 - Rent Increase:
Monthly rent of $1,200 [Original] in a city with a 7% [Increase] increase becomes what [New]?
$1,284 - Salary Increase:
A $50,000 [Original] salary increased by 8% [Increase] becomes what [New]?
$54,000
How to Use
- Enter the original value in the first box.
- Enter the increase percentage in the second box.
- The new value (after increase) appears instantly.
- Check "Round" if you want to keep the result to two decimal places.
- Save it to Memos with Enter or the "Add to Memos" button.
How It Works
The Increased Value calculator uses this formula:
Example: What is 100 increased by 25%?
100 plus 25% equals 125.
Original Before Increase CALCULATOR
Calculate the original value before a percentage increase, given the new value and percentage increase.
Practical Uses
- Budget (Pre-Increase):
What was the original wedding budget [Original] before a 25% [Increase] increase made it $6,250 [New]?
$5,000 - Investment (Pre-Growth):
What was the original Bitcoin investment [Original] before a 12% [Increase] growth made it worth $2,240 [New]?
$2,000 - Price Before Increase:
What was the original internet bill [Original] before a 5% [Increase] increase made it $126 [New]?
$120 - Rent Before Increase:
What was the original rent [Original] in a city before a 7% [Increase] increase made it $1,284 [New]?
$1,200 - Pre-Growth Population:
What was the original population of a city [Original] before a 3% [Increase] growth brought it to 103,000 [New] people?
100,000 - Salary Before Increase:
What was the original start-up salary [Original] before an 8% [Increase] salary increase made it $54,000 [New]?
$50,000
How to Use
- Enter the new value (after the increase) in the first box.
- Enter the increase percentage in the second box.
- The original value (before increase) appears instantly.
- Check "Round" if you want to keep the result to two decimal places.
- Save it to Memos with Enter or the "Add to Memos" button.
How It Works
The Original Before Increase calculator uses this formula:
Example: What was the original if 125 is after a 25% increase?
The original value was 100.
Decreased Value CALCULATOR
Calculate the new value after decreasing an original amount by a specific percentage.
Practical Uses
- Budget Cut:
A $10,000 [Original] party budget cut by 25% [Decrease] becomes what [New]?
$7,500 - Employee Reduction:
A 500 [Original]-person tech startup reduced by 10% [Decrease] leaves how many people [New]?
450 people - Energy Savings:
A $200 [Original] electricity bill reduced by 18% [Decrease] becomes what [New]?
$164 - Sale Discount:
A $300 [Original] outdoor jacket with a 30% [Decrease] discount costs what [New]?
$210 - Stock Price Drop:
A $45 [Original] car company stock declining by 12% [Decrease] becomes what [New]?
$39.60 - Weight Loss:
Weighing 80 [Original] kg and losing 15% [Decrease] for summer leaves what weight [New]?
68 kg
How to Use
- Enter the original value in the first box.
- Enter the decrease percentage in the second box.
- The new value (after decrease) appears instantly.
- Check "Round" if you want to keep the result to two decimal places.
- Save it to Memos with Enter or the "Add to Memos" button.
How It Works
The Decreased Value calculator uses this formula:
Example: What is 100 decreased by 25%?
100 minus 25% equals 75.
Original Before Decrease CALCULATOR
Calculate the original value before a percentage decrease, given the new value and percentage decrease.
Practical Uses
- Budget (Pre-Cut):
What was the original renovation budget [Original] before a 25% [Decrease] cut made it $3,750 [New]?
$5,000 - Investment (Pre-Loss):
What was the original stock portfolio [Original] before a 12% [Decrease] loss made it worth $1,760 [New]?
$2,000 - Expense Before Cut:
What were the original subscription costs [Original] before a 7% [Decrease] cut made them $930 [New]?
$1,000 - Salary Before Cut:
What was the original freelance income [Original] before an 8% [Decrease] drop made it $46,000 [New]?
$50,000 - Pre-Decline Population:
What was the original population of a city [Original] before a 3% [Decrease] decline left it at 97,000 [New] people?
100,000 - Price Before Discount:
What was the original price [Original] before a 5% [Decrease] local retailer discount made it $95 [New]?
$100
How to Use
- Enter the new value (after the decrease) in the first box.
- Enter the decrease percentage in the second box.
- The original value (before decrease) appears instantly.
- Check "Round" if you want to keep the result to two decimal places.
- Save it to Memos with Enter or the "Add to Memos" button.
How It Works
The Original Before Decrease calculator uses this formula:
Example: What was the original if 75 is after a 25% decrease?
The original value was 100.