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
You can type either a dot (.) or comma (,) as the decimal separator. The app converts it to your locale format automatically. For example:
- If your locale uses a dot (.), entering 10,5 is normalized to 10.5.
- If your locale uses a comma (,), entering 10.5 is normalized to 10,5.
- Thousands Separator
Thousands separators are optional when typing. You do not need to include them. When pasting, the app removes grouping separators and keeps one decimal separator (the last dot/comma), then converts it to your locale format. For example, "1,234.56" and "1.234,56" are both normalized to "1234.56" in dot-decimal locales and "1234,56" in comma-decimal locales. If you mean one thousand exactly, enter "1000".
- 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
- Click Save to copy the result to your clipboard and save it to your saved calculations 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 the calculation, 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.
Saved Calculations
- The current calculation is saved when you press Enter in the last field or click the Save calculation 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 saved calculations, 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 College final 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] Italian chain dinner bill comes to how much [Z]? $9
- Sale Discount: 20% [X] off a $80 [Y] pair of designer denim jeans saves you how much [Z]? $16
- Tax Calculation: 8% [X] NYC sales tax on a $250 [Y] pro 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 your list with Enter or the "Save calculation" 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 premium smartwatch? $200
- Pre-Tax Amount: 8% [X] of what pre-tax amount [Y] is $16 [Z] sales tax? $200
- Original Value: 15% [X] of what dinner bill [Y] is a 30 [Z] tip? 200
- Pre-Raise Salary: 10% [X] of what original base salary [Y] is a $5,000 [Z] raise? $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 your list with Enter or the "Save calculation" 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
- Batting Average: What is the batting average [X%] for a pro baseball player with 100 [Y] at-bats and 30 [Z] hits? 30%
- Rent Share: What percentage [X%] of your $4,000 [Y] monthly income goes to $800 [Z] rent in Houston? 20%
- Market Share: What is the leading EV maker's market share [X%] if total EV sales are $1,000,000 [Y] and the top seller 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 Bar 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 your list with Enter or the "Save calculation" 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 Big Box store manager's salary increase from $50,000 [Original] to $54,000 [New] represents what percentage raise [Change%]? 8%
- Stock Price Change: Streaming service stock going from $50 [Original] to $75 [New] represents what percentage change [Change%]? 50% increase
- Website Traffic Change: A drop in online craft shop visits from 10,000 [Original] to 8,500 [New] represents what percentage change [Change%]? 15% decrease
- Weight Loss: Weight dropping from 180 [Original] lbs to 162 [New] lbs on a Keto diet 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 your list with Enter or the "Save calculation" 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] theme park vacation budget increased by 25% [Increase] becomes what [New]? $6,250
- Investment Growth: A $2,000 [Original] Roth IRA growing by 12% [Increase] becomes what [New]? $2,240
- Population Growth: A city like Austin 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 Denver with a 7% [Increase] hike becomes what [New]? $1,284
- Salary Increase: A $50,000 [Original] nurse 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 your list with Enter or the "Save calculation" 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-Raise): What was the original wedding budget [Original] before a 25% [Increase] raise 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 Hike: What was the original cable TV bill [Original] before a 5% [Increase] hike made it $126 [New]? $120
- Rent Before Hike: What was the original rent [Original] in Chicago before a 7% [Increase] hike made it $1,284 [New]? $1,200
- Pre-Growth Population: What was the original population of Boise [Original] before a 3% [Increase] growth brought it to 103,000 [New] people? 100,000
- Salary Before Raise: What was the original startup salary [Original] before an 8% [Increase] raise 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 your list with Enter or the "Save calculation" 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] summer AC bill reduced by 18% [Decrease] becomes what [New]? $164
- Sale Discount: A $300 [Original] winter parka with a 30% [Decrease] discount costs what [New]? $210
- Stock Price Drop: A $45 [Original] auto stock declining by 12% [Decrease] becomes what [New]? $39.60
- Weight Loss: Weighing 180 [Original] lbs and losing 15% [Decrease] for summer leaves what weight [New]? 153 lbs
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 your list with Enter or the "Save calculation" 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 Detroit [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] store rewards 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 your list with Enter or the "Save calculation" 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.