Percentage Calculator
Quickly calculate percentages with our fast and accurate tool. Whether you want to find percentages, increase or decrease values, or solve percentage-based problems — get instant results without manual calculations.
Example: What is 20% of 500?
Result
100
20% of 500 = 100
All Four Formulas
% of a Number
Result = (P ÷ 100) × X
15% of 800 = 120
% Change
Change = ((New − Old) ÷ Old) × 100
200 → 250 = +25%
What % is X of Y
% = (X ÷ Y) × 100
50 of 200 = 25%
Reverse Percentage
Original = (Result ÷ %) × 100
120 is 80% of 150
What is a Percentage? — A Multi-Mode Percent Calculator Overview
A percentage is a number expressed as a fraction of 100. The word comes from the Latin per centum, meaning "per hundred". If you score 80 out of 100 on a test, you scored 80%. Percentages are used everywhere — from shopping discounts and taxes to interest rates and exam scores — because they give a universal, easy-to-compare scale.
This tool is a complete percent calculator: a percentage increase calculator and percentage decrease calculator, a percent change calculator, a discount percentage calculator, and a percentage difference calculator, all in one — built for U.S. users and a global audience.
Basic Percentage Formula
The most common percentage formula is:
Percentage = (Part ÷ Whole) × 100
This formula tells you how much one value represents out of another.
Example: If 40 students out of 200 passed, the pass percentage = (40 ÷ 200) × 100 = 20%.
How to Use This Calculator
No formulas, no guesswork — just enter your numbers and get instant results:
- 1Choose the type of calculation — % of a Number, % Change, X is % of Y, or Reverse %
- 2Enter the required values in the input fields
- 3Results appear instantly as you type — no need to click Calculate
- 4Use Copy or Share to save or send your result
How to Calculate Percentages
Finding a percentage of a number
- 1.Divide the percentage by 100
- 2.Multiply by the number
- 3.Example: 20% of 500 = (20÷100) × 500 = 100
Calculating percentage increase or decrease
- 1.Subtract original from new value
- 2.Divide by the original value
- 3.Multiply by 100
- 4.Example: 200 → 250 = (50÷200) × 100 = +25%
Finding what percentage X is of Y
- 1.Divide X by Y
- 2.Multiply by 100
- 3.Example: 50 of 200 = (50÷200) × 100 = 25%
Reverse percentage (finding the original)
- 1.Divide the result by the percentage
- 2.Multiply by 100
- 3.Example: 120 is 80% of ? = (120÷80) × 100 = 150
Percentage Increase vs. Decrease
Both use the same formula — the sign of the result tells you the direction. A positive result is an increase; negative is a decrease.
📈 Increase
New > Old → result is positive
500 → 600 = +20%
📉 Decrease
New < Old → result is negative
500 → 400 = −20%
Real-Life Uses of Percentages
Shopping Discounts
A 20% discount on $150 saves $30. Use the '% of Number' tab — also handy as a discount percentage calculator.
Profit & Loss
Bought at $800, sold at $1,000? That's a 25% profit. Use the '% Change' tab as a percent change calculator.
Exam Scores
Scored 72 out of 90? Use 'X is % of Y' to find you scored 80%.
Investment Returns
Portfolio grew from $10,000 to $15,000 — that's 50% growth. Use '% Change' as a percent increase calculator.
Loan Interest
8% of $100,000 = $8,000 interest per year. Use '% of Number'.
Food & Nutrition
A product has 12g protein per 80g serving — that's 15%. Use 'X is % of Y'.
Percentage Increase Calculator & Percentage Decrease Calculator — Formulas
These two formulas are the most frequently used in everyday life — from salary raises to sale prices. Together they cover the most common percent change calculator and percentage difference calculator use cases:
📈 Percentage Increase
% Increase = ((New − Old) ÷ Old) × 100
Used when value increases over time.
Example: Salary $50,000 → $60,000 = (10,000 ÷ 50,000) × 100 = 20% increase
📉 Percentage Decrease
% Decrease = ((Old − New) ÷ Old) × 100
Used when value decreases.
Example: Price $200 → $150 = (50 ÷ 200) × 100 = 25% decrease
Common Mistakes People Make
Small errors in percentage logic can lead to wrong decisions — especially with money. Here's what to avoid:
!Using the wrong base value
Always use the original (old) value as the base for percentage change. Using the new value gives a completely different — and incorrect — result.
!Confusing percentage with absolute difference
A change from 10 to 20 is a 100% increase, not just 10. Percentages measure relative change, not the raw gap.
!Forgetting to multiply by 100
The formula (Part ÷ Whole) gives a decimal — e.g. 0.25. You must multiply by 100 to get 25%. Skipping this step is the #1 error.
!Mixing up increase and decrease formulas
Both use the same formula with the old value as denominator. The sign of the result tells you the direction — positive = increase, negative = decrease.
Why Use This Calculator?
Mental percentage math is error-prone — especially under pressure or with non-round numbers. Here's why this tool saves you:
- ⚡Instant results — no waiting, no button press needed
- ✓Eliminates manual calculation errors
- 🔄Handles all 4 percentage types in one place
- 🎓Useful for students, professionals, and business owners alike
- 📱Works instantly on any device — mobile, tablet, or desktop
- 🕓Recent calculations saved locally so you can review your work
Final Thoughts
Percentage is a small concept — but it drives big decisions. Whether it's your exam marks, your salary raise, a shopping discount, or an investment return, understanding percentages gives you a real edge. Use this calculator regularly, stop guessing numbers, and make smarter decisions backed by accurate math.
Percentages are commonly used in finance, education, shopping, nutrition, and data analysis. The math on this page follows the standard formulas used in every reputable percent calculator worldwide. For official financial or academic decisions, always verify calculations with your institution or advisor.