🧮 Percent Calculator User Guide
The EVEDAYS Percent Calculator is a free web tool that quickly and accurately handles common percentage calculations. It operates instantly in your browser without server transmission and offers 4 modes. • Basic Percent: Performs basic operations like "What is 20% of 500?" or "80 is what % of 200?" • Rate of Change: Calculates the difference and rate of change (%) when a value changes from A to B. • Discount Price: Instantly computes discount amount and final price from original price and discount rate. • VAT Calculator: Calculates total with tax from supply price, or reverse-calculates supply price and tax from total. Useful for shopping, business expense management, school grade calculation, investment return analysis, and more.
📐 Basic Percentage Formulas
• B% of A = A × (B ÷ 100)
e.g.: 20% of 500 = 500 × 0.2 = 100
• B is what % of A = (B ÷ A) × 100
e.g.: 80 is what % of 200? = (80 ÷ 200) × 100 = 40%
• Rate of change = (New - Old) ÷ Old × 100
e.g.: 100 to 130 = (30 ÷ 100) × 100 = +30%
• Discount price = Original × (1 - Rate ÷ 100)
e.g.: $500 at 30% off = 500 × 0.7 = $350
• Price with VAT = Supply × (1 + Tax Rate ÷ 100)
e.g.: $1000 supply + 10% VAT = $1,100
💡 FAQ
Q. Why is the default VAT rate 10%?
A. Because the standard VAT rate in South Korea is 10%. You can freely change it to match other countries' tax rates (Japan 10%, US varies by state).
Q. Are decimal results accurate?
A. We use IEEE 754 floating-point arithmetic for very high precision. However, extremely small values may have minor floating-point errors.
Q. Is my input data saved?
A. No. This calculator does not store any data. Refreshing the page resets everything.