Find Percentage Calculator | % of Number & Marks

  • Adam
  • November 13, 2025

Free percentage finder. Calculate % of a number, find what % one number is of another, % change between numbers & marks percentage. Instant results + formulas.

Find Percentage Calculator – Calculate Percentage of Number & Marks

The find percentage calculator helps you calculate percentages instantly for any scenario: find what percentage one number is of another (e.g., 25 is what % of 100?), calculate a percentage of a number (e.g., what is 20% of 500?), find percentage between two numbers (difference or change), or calculate percentage of marks (e.g., 450 out of 600). This comprehensive percentage finder covers all common percentage calculations with step-by-step solutions, formulas, and real-world examples for students, professionals, and everyday use.

🔢 Find Percentage of a Number

Calculate: What is X% of Y?

Enter the percentage (e.g., 20)
The total number

Percentage Calculation Result

Answer
100
Percentage
20%
Of Number
500

Step-by-Step Calculation

Step Calculation
Formula Result = (% / 100) × Number
Convert to decimal 20 / 100 = 0.20
Multiply 0.20 × 500
Final Answer 100

📊 Find What Percentage

Calculate: X is what % of Y?

The part or portion
The total or whole

Percentage Result

Answer
25%
Part
25
Whole
100

Step-by-Step Calculation

Step Calculation
Formula % = (Part / Whole) × 100
Divide 25 / 100 = 0.25
Convert to percentage 0.25 × 100
Final Answer 25%

📈 Find Percentage Change/Difference

Calculate: % increase or decrease between two numbers

Starting or old value
Ending or new value

Percentage Change Result

Percentage Change
+50%
Absolute Change
50
Change Type
Increase

Step-by-Step Calculation

Step Calculation
Formula % Change = [(New - Old) / Old] × 100
Find difference 150 - 100 = 50
Divide by original 50 / 100 = 0.50
Convert to percentage 0.50 × 100
Final Answer +50%

🎓 Find Percentage of Marks

Calculate: Score percentage and grade

Total marks scored
Maximum possible marks

Marks Percentage Result

Percentage
75%
Grade
B
Marks Lost
150

Detailed Breakdown

Item Value
Marks Obtained 450
Total Marks 600
Marks Lost 150
Calculation (450 / 600) × 100
Percentage 75%
Grade B

How to Find Percentage: Complete Guide

Finding percentages is one of the most common mathematical calculations used in everyday life—from calculating discounts and test scores to understanding statistics and financial data. This comprehensive guide covers all methods to find percentages with formulas, examples, and practical applications.

Method 1: Find Percentage of a Number

This method answers the question: "What is X% of Y?" It's used when you need to find a portion of a total.

Formula to Find Percentage of a Number:

Result = (Percentage / 100) × Number

Alternative Formula:

Result = (P% / 100) × N

Example 1: What is 20% of 500?

Given: Percentage = 20%, Number = 500

Step 1: Convert percentage to decimal = 20 / 100 = 0.20

Step 2: Multiply by the number = 0.20 × 500 = 100

Answer: 20% of 500 is 100

Real-world: A 20% discount on a $500 item saves you $100

Example 2: What is 8% of 1,250?

Given: Percentage = 8%, Number = 1,250

Step 1: Convert to decimal = 8 / 100 = 0.08

Step 2: Multiply = 0.08 × 1,250 = 100

Answer: 8% of 1,250 is 100

Real-world: 8% sales tax on $1,250 purchase = $100 tax

Method 2: Find What Percentage One Number Is of Another

This method answers: "X is what percentage of Y?" It's used to find the percentage relationship between two numbers.

Formula to Find What Percentage:

Percentage = (Part / Whole) × 100

Alternative:

% = (X / Y) × 100

Example 1: 25 is what percent of 100?

Given: Part = 25, Whole = 100

Step 1: Divide part by whole = 25 / 100 = 0.25

Step 2: Multiply by 100 = 0.25 × 100 = 25%

Answer: 25 is 25% of 100

Real-world: If you answered 25 out of 100 questions correctly, your score is 25%

Example 2: 450 is what percent of 600?

Given: Part = 450, Whole = 600

Step 1: Divide = 450 / 600 = 0.75

Step 2: Convert to percentage = 0.75 × 100 = 75%

Answer: 450 is 75% of 600

Real-world: If you scored 450 out of 600 marks, your percentage is 75%

Method 3: Find Percentage Change Between Two Numbers

This method calculates the percentage increase or decrease from one number to another.

Formula for Percentage Change:

% Change = [(New Value - Old Value) / Old Value] × 100

Positive result = Percentage Increase

Negative result = Percentage Decrease

Example 1: Percentage Increase from 100 to 150

Given: Old Value = 100, New Value = 150

Step 1: Find difference = 150 - 100 = 50

Step 2: Divide by original = 50 / 100 = 0.50

Step 3: Convert to percentage = 0.50 × 100 = 50%

Answer: +50% increase (or 50% increase)

Real-world: Price increased from $100 to $150 = 50% increase

Example 2: Percentage Decrease from 200 to 150

Given: Old Value = 200, New Value = 150

Step 1: Find difference = 150 - 200 = -50

Step 2: Divide by original = -50 / 200 = -0.25

Step 3: Convert to percentage = -0.25 × 100 = -25%

Answer: -25% decrease (or 25% decrease)

Real-world: Price dropped from $200 to $150 = 25% discount

Find Percentage of Marks (Academic)

Calculating percentage of marks is essential for students to know their academic performance:

Formula for Marks Percentage:

Percentage = (Marks Obtained / Total Marks) × 100

Standard Grading Scale

Percentage Range Grade Description
90-100% A Excellent / Outstanding
80-89% B Very Good / Above Average
70-79% C Good / Average
60-69% D Satisfactory / Below Average
Below 60% F Fail / Unsatisfactory

Common Marks Percentage Examples:

  • 450 out of 600: (450 / 600) × 100 = 75% (Grade B)
  • 85 out of 100: (85 / 100) × 100 = 85% (Grade B)
  • 540 out of 600: (540 / 600) × 100 = 90% (Grade A)
  • 360 out of 500: (360 / 500) × 100 = 72% (Grade C)

Quick Percentage Calculation Methods

Mental Math Shortcuts

  • 10%: Move decimal point one place left → 10% of 350 = 35
  • 1%: Move decimal point two places left → 1% of 800 = 8
  • 5%: Find 10% and divide by 2 → 5% of 200 = 20 ÷ 2 = 10
  • 25%: Divide by 4 → 25% of 80 = 80 ÷ 4 = 20
  • 50%: Divide by 2 → 50% of 150 = 150 ÷ 2 = 75
  • 75%: Find 50% + 25% → 75% of 100 = 50 + 25 = 75

Common Percentage Values

Percentage Decimal Fraction Quick Calc
10% 0.10 1/10 Divide by 10
20% 0.20 1/5 Divide by 5
25% 0.25 1/4 Divide by 4
33.33% 0.3333 1/3 Divide by 3
50% 0.50 1/2 Divide by 2
75% 0.75 3/4 Multiply by 0.75

Real-World Percentage Applications

Shopping & Discounts

  • 30% off $80 item: Discount = 0.30 × 80 = $24 (Pay $56)
  • Buy 2 get 25% off: Save 25% on second item
  • Clearance 70% off: Pay only 30% of original price

Taxes & Tips

  • 8% sales tax on $50: Tax = 0.08 × 50 = $4 (Total $54)
  • 15% tip on $60 bill: Tip = 0.15 × 60 = $9 (Total $69)
  • 20% gratuity: 20% of bill amount

Finance & Investments

  • 5% annual interest: $10,000 × 0.05 = $500 interest
  • Stock gain of 15%: $1,000 investment = $150 profit
  • Inflation rate 3%: Purchasing power decreases 3% yearly

Frequently Asked Questions

How do you find the percentage of a number?
Use formula: Result = (Percentage / 100) × Number. Steps: 1) Convert percentage to decimal by dividing by 100, 2) Multiply decimal by the number. Example: What is 20% of 500? 20/100 = 0.20, then 0.20 × 500 = 100. Answer: 100. Real-world: 20% discount on $500 item saves $100. Quick method for 10%: just move decimal point left once (10% of 500 = 50). For other percentages, find 10% first then multiply (20% = 10% × 2).
How do you find what percentage one number is of another?
Use formula: Percentage = (Part / Whole) × 100. Steps: 1) Divide the first number (part) by second number (whole), 2) Multiply result by 100 to get percentage. Example: 25 is what % of 100? 25/100 = 0.25, then 0.25 × 100 = 25%. Answer: 25%. Real-world: Scored 45 out of 60 points = (45/60) × 100 = 75% grade. Remember: smaller number divided by larger number gives fraction, multiply by 100 for percentage.
How do you calculate percentage between two numbers?
Use formula: % Change = [(New - Old) / Old] × 100. Steps: 1) Subtract old value from new value, 2) Divide by old value, 3) Multiply by 100. Example: Change from 100 to 150? (150-100)/100 × 100 = 50% increase. From 200 to 150? (150-200)/200 × 100 = -25% decrease. Positive = increase, negative = decrease. Real-world: Price rose from $50 to $65 = (65-50)/50 × 100 = 30% increase. Salary dropped from $60K to $54K = -10% decrease.
How do you find percentage of marks?
Use formula: Percentage = (Marks Obtained / Total Marks) × 100. Steps: 1) Divide marks scored by maximum marks, 2) Multiply by 100. Example: Scored 450 out of 600 marks = (450/600) × 100 = 75%. Grading: 90-100% = A, 80-89% = B, 70-79% = C, 60-69% = D, Below 60% = F. Multiple subjects: Add all marks obtained, divide by total possible marks. Example: 85+90+78 = 253 out of 300 = (253/300) × 100 = 84.3% (Grade B).
What is the fastest way to calculate percentages mentally?
Quick methods: 10% = move decimal left once (10% of 240 = 24). 5% = half of 10% (5% of 240 = 12). 1% = move decimal left twice (1% of 240 = 2.4). 25% = divide by 4 (25% of 80 = 20). 50% = divide by 2 (50% of 150 = 75). 20% = find 10% and double it (20% of 240 = 48). 15% = 10% + 5% (15% of 240 = 24 + 12 = 36). For odd percentages like 37%, find 10% three times plus 7×1%. Practice with money amounts for real-world speed.
How do you convert percentage to decimal and vice versa?
Percentage to decimal: Divide by 100 (remove % sign, move decimal 2 places left). Examples: 25% = 0.25, 8.5% = 0.085, 150% = 1.50, 0.5% = 0.005. Decimal to percentage: Multiply by 100 (move decimal 2 places right, add %). Examples: 0.75 = 75%, 0.06 = 6%, 1.25 = 125%, 0.005 = 0.5%. Remember: Percent means "per hundred" so dividing/multiplying by 100 converts between forms. Always convert to decimal before calculations.
What are common percentage calculation mistakes to avoid?
Common errors: 1) Forgetting to divide by 100 when converting % to decimal (using 20 instead of 0.20). 2) Dividing in wrong order (whole/part instead of part/whole). 3) Not multiplying by 100 when finding percentage (saying 0.25 instead of 25%). 4) Confusing percentage OF vs percentage IS (20% of 100 = 20, vs 20 is 20% of 100). 5) Using wrong base for % change (using new value instead of old). 6) Adding percentages directly (two 50% discounts ≠ 100% off, it's 75% off). Double-check: Does answer make logical sense?

Percentage Calculation Practice Problems

Practice these common scenarios:

  1. Discount: What is 35% off a $120 jacket? (Answer: $42 discount, pay $78)
  2. Tax: What is 7.5% tax on $250? (Answer: $18.75 tax, total $268.75)
  3. Tip: What is 18% tip on $85 bill? (Answer: $15.30 tip, total $100.30)
  4. Test Score: 42 out of 50 questions correct = what %? (Answer: 84%)
  5. Increase: Salary went from $50K to $58K = what % raise? (Answer: 16% increase)
  6. Decrease: Price dropped from $80 to $64 = what % off? (Answer: 20% discount)

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