Percentage Calculator
Calculate percentages with 5 modes: basic, increase, decrease, change, and difference.
Calculate a percentage of a number
About Percentage Calculator
This tool offers five percentage calculation modes: find a percentage of a number, determine what percentage one number is of another, increase or decrease a number by a percentage, and calculate the percentage change between two values. Each calculation shows both the result and the formula used, making it useful for learning as well as quick computations. Perfect for calculating discounts, tips, tax amounts, grade percentages, financial growth rates, or any situation involving percentage math.
The Five Percentage Calculations You Actually Need
Percentage calculations trip people up because "percentage" is used to mean several different things in everyday conversation. "What is 20% of 80?" is different from "80 is what percent of 200?" which is different from "what is the percentage increase from 80 to 100?" This calculator handles all five common scenarios clearly so you always get the right answer for what you are actually trying to find.
Percentage Formulas Explained
- X% of Y — multiply Y by X and divide by 100. Example: 15% of 200 = (200 × 15) ÷ 100 = 30.
- X is what % of Y — divide X by Y and multiply by 100. Example: 30 is what % of 200 = (30 ÷ 200) × 100 = 15%.
- Percentage increase — ((new − old) ÷ old) × 100. Example: from 80 to 100 = ((100 − 80) ÷ 80) × 100 = 25% increase.
- Percentage decrease — ((old − new) ÷ old) × 100. Example: from 100 to 80 = ((100 − 80) ÷ 100) × 100 = 20% decrease.
- Percentage difference — |a − b| ÷ ((a + b) ÷ 2) × 100. Used when neither value is the "original" — comparing two equal-footing values.
Real-World Applications
- Calculating discounts — a 30% discount on a Rs. 2,500 item saves Rs. 750.
- VAT and sales tax — add 17% tax to a price to find the total.
- Grade calculations — your score as a percentage of total marks.
- Business metrics — month-over-month revenue growth percentages.
- Investment returns — percentage gain or loss on a portfolio position.
Knowledge Base
The Percentage Calculator handles five common percentage calculations: basic percentage, percentage increase, percentage decrease, percentage change, and percentage difference. It eliminates mental math errors and saves time.
- 1Choose the calculation type from the five available modes.
- 2Enter the required values in the input fields.
- 3View the instant result with the full calculation breakdown.
All calculations happen locally in your browser with instant results. No data is sent to any server, ensuring your financial and mathematical calculations remain completely private and secure.
What are the 5 calculation modes?
The five modes are: (1) Basic percentage (X% of Y), (2) Percentage increase (X to Y is a Z% increase), (3) Percentage decrease, (4) Percentage change between two values, and (5) Percentage difference between two values.
Does it show the calculation steps?
Yes. Each calculation shows the full breakdown including the formula used and step-by-step working, so you can understand how the result was derived.