Percentage Calculator

Calculate a percentage of any number. Perfect for tips, taxes, and discounts.

• Formula: X ÷ 100 × Y
• Example: 20% of 150 = 30
• Use cases: Restaurant tips, sales tax, discount amounts

Find what percentage one number represents of another. Great for test scores and ratios.

• Formula: X ÷ Y × 100
• Example: 45 is 75% of 60
• Use cases: Test scores, completion rates, portion calculations

Add or subtract a percentage from a base value. Ideal for markups and discounts.

• Increase formula: Value + (Value × % ÷ 100)
• Decrease formula: Value - (Value × % ÷ 100)
• Example: $80 decreased by 25% = $60
• Use cases: Sale prices, price markups, budget adjustments

Calculate the percentage increase or decrease between two values. Essential for tracking growth or decline.

• Formula: (New - Old) ÷ Old × 100
• Shows increase with green badge or decrease with red badge
• Example: From $40 to $52 = +30% increase
• Use cases: Price changes, growth rates, performance tracking

Find the relative difference between two values without considering direction.

• Formula: |A - B| ÷ ((A + B) ÷ 2) × 100
• Example: Difference between 45 and 55 = 20%
• Use cases: Comparing measurements, analyzing variations, quality control

Percent change measures how much a value increased or decreased from an original value. It has a direction (positive for increase, negative for decrease) and considers one value as the baseline.

Percent difference compares two values without considering which is the "original" - it simply measures how different they are from each other relative to their average. This is useful when neither value is inherently the starting point.

Use the "Increase/Decrease by %" mode and follow these steps:

• Select "Decrease" from the dropdown
• Enter the original price in the first field
• Enter the discount percentage in the second field
• The result shows the final price after discount

Example: A $100 item with 20% off → Enter 100 and 20%, result is $80 (you save $20).

Use the "What is X% of Y?" mode:

• Enter the tip percentage (common values: 15%, 18%, or 20%)
• Enter your bill amount
• The result shows the tip amount to add

Example: For a $50 bill with 18% tip → Enter 18 and 50, result is $9 tip (total bill: $59).

Use the "X is what % of Y?" mode:

• Enter your score (points earned) as X
• Enter the total possible points as Y
• The result shows your percentage score

Example: You got 45 correct out of 60 questions → Enter 45 and 60, result is 75%.

The calculator handles division by zero gracefully by displaying "-" instead of an error message. This prevents confusion and maintains a clean interface.

Division by zero can occur in these scenarios:

• Percent change: When the original value is 0
• Percent difference: When both values are 0
• X is what % of Y: When Y is 0

Yes! The calculator fully supports decimal numbers in all input fields. You can enter values like:

• Percentages: 12.5%, 7.25%, 99.99%
• Amounts: $19.99, 45.67, 1000.50
• Precise calculations: 33.333, 66.667

Simply type the decimal point as you would normally, and the calculator will handle it accurately.

The preset dropdown only appears when the percentage input field is completely empty. This is by design to prevent accidental overwrites of your custom values.

To access presets:

• Clear any existing value in the percentage field
• Click the empty field
• The dropdown with common percentages will appear

No. All calculations happen locally in your browser using JavaScript. Your numbers are never sent to any server, and we don't store any calculation history.

Yes! The calculator supports standard keyboard navigation:

• Tab - Move to the next input field
• Shift + Tab - Move to the previous input field
• 0-9 - Enter numeric values
• . (period) - Enter decimal point
• - (minus) - Enter negative numbers
• Enter - Confirm value in current field

All standard text editing shortcuts (Ctrl+C, Ctrl+V, Ctrl+A) work normally in input fields.