Free Percentage & Discount Calculator (2026)
Solve percentage of a number, percentage increase/decrease, sale discounts, and markup margins instantly.
Mastering Percentage Calculations for Business, Finance & E-Commerce
Percentages are the universal language of business margins, tax liabilities, investment returns, and retail sales. Whether you are an online seller pricing inventory, a student checking test scores, or an investor tracking portfolio gains, understanding how to apply the core percentage formulas prevents costly math mistakes.
1. Core Percentage Formulas
- Standard Percentage Formula:
Result = (Percentage ÷ 100) × Total Value - Percentage Difference / Growth Rate:
Percentage Change = ((New Value − Old Value) ÷ Old Value) × 100 - Discount Price Formula:
Sale Price = Original Price × (1 − (Discount % ÷ 100))
2. Margin vs. Markup: The Crucial E-Commerce Difference
Many new business owners confuse Markup (percentage added to cost price) with Gross Margin (percentage of selling price retained as profit). A 50% markup on a ₹100 product equals a ₹150 selling price, which yields a 33.3% gross profit margin—not 50%! Always calculate net margins before committing to discount coupons.
Frequently Asked Questions (FAQ)
How do I calculate what percentage one number is of another?
Divide the smaller number by the total number, then multiply by 100. For example, 75 divided by 300 equals 0.25, multiplied by 100 gives 25%.
How do I calculate a discount in my head?
To calculate 20% off: find 10% by moving the decimal point one place to the left, then double that number. For ₹800, 10% is ₹80, so 20% is ₹160 off (final price ₹640).