Percentage Calculator – Online Free Tool
Free percentage calculator for basic percentage, percent change calculator, proportion and discount. Real-time, precise, perfect for shopping discounts, salary increase, test scores and ROI.
Start Calculating
How to calculate percentage
- Basic: Result = Base × Percentage ÷ 100. Example: 15% of 200 = 30.
- Percent change: (New - Old) ÷ Old × 100.
- What percent: Part ÷ Total × 100. Example: 90/120 = 75%.
- Discount: Final price = Original × (100 - Discount%) ÷ 100; Saving = Original - Final.
Examples
- Discount: $120 with 25% → $90.
- Salary increase: $3,000 to $3,450 → +15%.
- Score: 90/120 → 75%.
Input Values
Result
Example Usage
Features
Three Calculation Modes
Supports basic percentage, percentage change, and proportion calculations
Real-time Calculation
Instant results as you type, no need to click calculate
High Precision
Supports decimal calculations with high precision results
Secure Usage
All calculations are performed locally, no data uploaded
Helpful Tips
For shopping discounts: Original Price × (100 - Discount Percentage) ÷ 100 = Discounted Price
Calculate taxes: Product Price × Tax Rate Percentage ÷ 100 = Tax Amount
Investment ROI: (Current Value - Initial Investment) ÷ Initial Investment × 100 = ROI%
Test scores: Score ÷ Total Score × 100 = Score Percentage
Tip calculation: Bill Amount × Tip Percentage ÷ 100 = Tip Amount
How to Use
Choose Calculation Mode
Select basic percentage, percentage change, or proportion calculation mode based on your needs
Enter Values
Enter the values to calculate in the corresponding input fields, supports integers and decimals
View Results
The system automatically calculates and displays results with detailed calculation process explanations
Frequently Asked Questions
How to calculate a percentage of a number?
+
How to calculate a percentage of a number?
Select "Basic Percentage" mode, enter the base number and percentage rate. For example: to calculate 15% of 200, enter base 200, percentage 15, result is 30. Formula: Base × Percentage ÷ 100 = Result.
How to calculate growth rate or decrease rate?
+
How to calculate growth rate or decrease rate?
Select "Percentage Change" mode, enter the original value and new value. The system will automatically calculate the percentage change. Formula: (New Value - Original Value) ÷ Original Value × 100 = Percentage Change. Positive values indicate growth, negative values indicate decrease.
How to calculate what percentage one number is of another?
+
How to calculate what percentage one number is of another?
Select "Proportion Calculation" mode, enter the part value and total value. For example: what percentage is 90 out of 120, enter part 90, total 120, result is 75%. Formula: Part ÷ Total × 100 = Percentage.
Does the percentage calculator support decimals?
+
Does the percentage calculator support decimals?
Yes, our percentage calculator fully supports decimal calculations. You can enter decimal values like 12.5, 0.75, etc., and the system will maintain high precision calculations and display accurate results.
What is the precision of calculation results?
+
What is the precision of calculation results?
Our calculator uses high-precision algorithms, typically preserving up to 4 decimal places. This precision is sufficient for most daily calculation needs. If higher precision is required, professional mathematical calculation software can be used.