- How to Calculate a Percentage?
- How Are Percentages Used in Everyday Life?
- How to Calculate a Percentage Increase?
- How to Calculate a Percentage Decrease?
- How to Calculate a Reverse Percentage?
- How to Convert a Percentage to a Grade?
- How to Calculate GST (Goods and Services Tax) in New Zealand?
- How to Calculate Win Percentage in Sports?
- How to Calculate a Percentage in Excel?
Percentages are everywhere—whether you’re calculating discounts while shopping, tracking exam scores, or comparing mortgage rates. Understanding percentages helps with budgeting, investments, fitness, and even sports statistics.
A percentage expresses a number as a fraction of 100 and is widely used in finance, education, health, and daily life to analyse data and make informed decisions.
How to Calculate a Percentage?
To calculate a percentage, use this simple formula:
Percentage = (Part ÷ Total) × 100
How to calculate a percentage?
You have 10 Whittaker’s chocolate squares, and you eat 4. What percentage have you eaten?
- Divide the part (4 squares) by the total (10 squares): 4 ÷ 10 = 0.40
- Multiply by 100: 0.40 × 100 = 40%
So, you ate 40% of the chocolate.
If you need a quick answer, try our online percentage calculator!
How Are Percentages Used in Everyday Life?
Percentages help compare values, track changes, and improve financial decisions. Here are some real-world examples:
Shopping: Discounts & Sales
You're shopping at The Warehouse, and a jacket originally priced at $150 is 25% off.
To calculate the discount: 150 × 0.25 = 37.50
You save $37.50, and the final price is: 150 - 37.50 = $112.50
Retail stores use percentage discounts to attract customers and boost sales.
Finance: Mortgage & Savings Rates
Percentages are key in banking, especially for mortgage rates and savings interest.
If your bank offers 3.5% interest on a $10,000 savings account, your yearly earnings are:
10,000 × 0.035 = 350
So, your savings earn $350 per year. The higher the percentage, the more you earn!
Health & Nutrition: Food Labels
Ever checked a food label and seen “6% sugar” on a juice bottle? That means in 100mL of juice, 6mL is sugar.
If a bottle contains 500mL, how much sugar does it have?
500 × 0.06 = 30mL of sugar
Understanding percentages in nutrition helps you make healthier choices.
How to Calculate a Percentage Increase?
A percentage increase shows how much something has grown compared to its original value.
Formula:
Percentage Increase = ((New Value − Old Value) ÷ Old Value) × 100
How to calculate a percentage increase?
Your power bill was $200 last month, but this month it’s $250.
- Find the difference: 250 - 200 = 50
- Divide by the original value: 50 ÷ 200 = 0.25
- Multiply by 100: 0.25 × 100 = 25%
Your electricity bill increased by 25%. Try our percentage increase calculator for quick calculations!
How to Calculate a Percentage Decrease?
A percentage decrease shows how much something has reduced from its original value.
Formula:
Percentage Decrease = ((Old Value − New Value) ÷ Old Value) × 100
How to Calculate a Percentage Decrease?
A new iPhone originally cost $1,800, but now it's on sale for $1,500.
- Find the difference: 1,800 - 1,500 = 300
- Divide by the original price: 300 ÷ 1,800 = 0.1667
- Multiply by 100: 0.1667 × 100 = 16.67%
So, the iPhone is 16.67% cheaper.
How to Calculate a Reverse Percentage?
A reverse percentage helps you find the original price before a discount or increase.
Reverse percentage calculation
You bought a laptop for $1,350 after a 10% discount, but you want to know the original price.
Since $1,350 represents 90% of the original price:
1,350 ÷ 0.90 = 1,500
So, the original price was $1,500 before the discount.
How to Convert a Percentage to a Grade?
New Zealand schools and universities use percentage-based grading systems.
NZ Grade Conversion Table:
| Percentage | Grade |
|---|---|
| 90-100% | A+ (Outstanding) |
| 80-89% | A (Excellent) |
| 70-79% | B (Good) |
| 60-69% | C (Satisfactory) |
| 50-59% | D (Pass) |
| Below 50% | F (Fail) |
If you scored 82% in a university subject, your grade is A (Excellent).
How to Calculate GST (Goods and Services Tax) in New Zealand?
New Zealand has a 15% GST on most goods and services.
To add GST to a price:
Price with GST = Original Price × 1.15
To remove GST from a price:
Original Price = Price with GST ÷ 1.15
For example
A new TV costs $1,200 including GST. To find the pre-GST price:
1,200 ÷ 1.15 = 1,043.48
So, the TV costs $1,043.48 before GST.
How to Calculate Win Percentage in Sports?
Win percentage is useful for sports, gaming, and performance tracking.
Formula:
Win Percentage = (Wins ÷ Total Games) × 100
For example
Let's take the Super Rugby Team Stats for example:
The Crusaders played 20 matches, winning 15.
(15 ÷ 20) × 100 = 75%
So, their win percentage is 75%.
How to Calculate a Percentage in Excel?
Microsoft Excel makes percentage calculations easy.
Step-by-Step Guide:
- Enter your data in two columns (e.g., "Part" and "Total").
- In the next column, enter this formula:=(A2 ÷ B2) × 100
- Press Enter, and Excel will calculate the percentage.
- Drag the formula down to apply it to multiple rows.
This method works for sales targets, grades, or financial data.
Percentages are useful in everyday life, from budgeting and savings to discounts and sports stats. Whether you’re estimating GST, tracking fitness progress, or finding the best shopping deals, knowing how to calculate percentages helps you make smarter decisions.
For quick calculations, try our online percentage calculator.
