📖 Help & Instructions
Getting Started
Select a calculation type from the tabs at the top. Each calculator has its own input fields and formulas.
Calculation Types
- Percentage of Number: Find what X% of Y is (e.g., 25% of 100 = 25)
- What Percentage: Find what percentage X is of Y (e.g., 25 is 25% of 100)
- Increase/Decrease: Calculate percentage increase or decrease from a value
- Percentage Difference: Find the difference between two values as a percentage
- Add/Subtract Percentage: Add or subtract a percentage from a number
- Reverse Percentage: Find the original value before a percentage change
- Compound: Calculate compound interest/growth over time
- Change Over Time: Calculate percentage change between initial and final values
- Fraction to %: Convert a fraction to a percentage
- Decimal to %: Convert a decimal to a percentage
- Percentage Error: Calculate experimental error as a percentage
- Margin/Markup: Calculate profit margin and markup
- Discount: Calculate price after discount
- Tax: Calculate price including tax
- Tip: Calculate total bill with tip
Features
- Formula Display: Each calculation shows the formula used
- Copy Result: Click "Copy Result" to copy the answer to clipboard
- History: All calculations are saved in the history section
- Save Percentages: Save commonly used percentages for quick access
- Export: Export calculation history to CSV or JSON format
- API Access: Use the provided endpoints for programmatic access
- Spreadsheet Integration: Use the provided formulas in Excel/Google Sheets
Tips
- Enter numbers only (no symbols like $ or %)
- Use decimal points for precise calculations
- History is automatically saved to your browser's local storage
- Click on any saved percentage to quickly use it in calculations