Percentage Calculators Hub

Whether you need to answer a simple question such as “What is 20% of 150?” or compare a business cost with its selling price, this hub gives you the appropriate calculator without requiring complicated manual calculations.

What Can You Calculate With This Percentage Hub?

The Percentage Calculators Hub brings several common percentage calculations together:

• Percentage of a number — Find X% of any number.
• What percent is X of Y? — Determine one number as a percentage of another.
• Percentage increase — Add a percentage increase to an original value.
• Percentage decrease — Subtract a percentage decrease from an original value.
• Percent change — Compare an old value with a new value and calculate the percentage difference.
• Discount calculator — Find the amount saved and final price after a discount.
• Markup calculator — Add a markup percentage to a cost to calculate a selling price.
• Profit margin calculator — Calculate profit as a percentage of revenue.
• Reverse percentage calculator — Work backwards from a final value to estimate the original value before a percentage increase or decrease.

Instead of searching for separate tools for each calculation, you can use the calculators on this page as a single percentage calculation hub. If you’re looking for a different kind of financial calculator entirely, our Share Incentive Plan Calculator and full Calculators hub cover UK share scheme contributions, tax savings, and US equity compensation.

Formulas

The Percentage Formulas Behind Every Tool on This Page

Understanding the formula behind a calculator can make percentage problems much easier to solve manually. Each tool on this page uses a standard mathematical formula.

Calculator	Formula
X% of Y	(X ÷ 100) × Y
What percent is X of Y?	(X ÷ Y) × 100
Percentage increase	Original + (Original × % ÷ 100)
Percentage decrease	Original − (Original × % ÷ 100)
Percent change	((New − Old) ÷ |Old|) × 100
Discount / final price	Price − (Price × Discount% ÷ 100)
Markup / selling price	Cost + (Cost × Markup% ÷ 100)
Profit margin	((Revenue − Cost) ÷ Revenue) × 100
Reverse percentage	Final ÷ (1 + % ÷ 100)

The calculators apply these formulas automatically, so you only need to enter the values relevant to your calculation.

What Is a Percentage?

A percentage is a way of expressing a number as a portion of 100. The word “percent” literally refers to “per hundred.”

For example: 10% means 10 out of 100. 25% means 25 out of 100. 50% means 50 out of 100. 75% means 75 out of 100. 100% means the entire amount.

Percentages are commonly written using the % symbol. For example, 25% can also be written as 25 ÷ 100, which equals 0.25. This makes percentage calculations easier because you can convert the percentage to a decimal before multiplying.

For example, 25% of 200: 25 ÷ 100 = 0.25, then 0.25 × 200 = 50. Therefore, 25% of 200 is 50.

How to Use the Percentage Calculators

Using the calculators is straightforward. Select the calculation you need, enter the required numbers, and the result will update as you type.

For example, if you want to find 15% of 240, open the “% Of a Number” calculator above and enter a Percentage of 15 and a Number of 240. The calculator returns 36. You can then use the result immediately without manually applying the formula.

For calculations involving two values, such as percentage change, simply enter the original and new values. The calculator handles the arithmetic automatically.

Why Use a Percentage Calculator?

Percentage calculations appear in many areas of everyday life. You may need to calculate a discount while shopping, determine a tip at a restaurant, compare a salary increase, work out a business markup, calculate profit margin, or solve a percentage problem for school.

Although the formulas are simple, calculations can become inconvenient when several steps are involved. A percentage calculator helps reduce arithmetic mistakes and saves time. These tools are particularly useful when:

• You need an answer quickly.
• You are working with decimals.
• You are comparing multiple values.
• You need to calculate discounts.
• You are pricing products.
• You are checking business margins.
• You are studying mathematics.
• You want to verify a calculation you made manually.

Worked examples

One Example for Every Percentage Tool

1. Percentage of a Number

Question: What is 15% of 240?

Formula: 15 ÷ 100 × 240 = 36. Answer: 36. This type of calculation can be used for tips, taxes, commissions, discounts, and many other percentage-based amounts.

2. What Percent Is X of Y?

Question: 36 is what percentage of 240?

Formula: 36 ÷ 240 × 100 = 15%. Answer: 15%. This is useful when you know the part and the total but need to determine the percentage represented by the part.

3. Percentage Increase

Question: Increase 80 by 25%.

First calculate 25% of 80: 80 × 0.25 = 20. Then add the increase: 80 + 20 = 100.

4. Percentage Decrease

Question: Decrease 80 by 25%.

25% of 80 is 20. 80 − 20 = 60.

5. Percent Change

Question: A value changes from 50 to 65. What is the percentage change?

Formula: ((65 − 50) ÷ 50) × 100 = (15 ÷ 50) × 100 = 30%. The value increased by 30%.

6. Discount

Question: An $80 product is discounted by 20%.

Discount: 80 × 20% = $16. Final price: $80 − $16 = $64. You save $16 and pay $64.

7. Markup

Question: A product costs $50 and has a 40% markup.

Markup: $50 × 40% = $20. Selling price: $50 + $20 = $70.

8. Profit Margin

Question: A product sells for $70 and costs $50.

Profit: $70 − $50 = $20. Profit margin: ($20 ÷ $70) × 100 = 28.6%.

9. Reverse Percentage

Question: A product costs $100 after a 25% increase. What was the original price?

Original price: 100 ÷ 1.25 = $80.

Percentage Increase vs. Percentage Decrease

Percentage increase and percentage decrease describe changes in a value from a known starting point. If a value increases by 20%, you add 20% of the original value — for example, $100 + 20% = $120. If the same $100 value decreases by 20%, $100 − 20% = $80.

An important point is that percentage changes are based on the starting value. A 20% increase from $100 gives $120. A 20% decrease from $120 gives $96, not $100 — because the second calculation uses $120 as the starting value.

Percentage Change vs. Percentage Increase

These terms are related but are not always used in exactly the same way. Percentage increase is normally used when the value moves upward and you already know the percentage increase you want to apply — for example, “Increase 500 by 10%” gives 550.

Percentage change is normally used when you have an old value and a new value and want to determine how much the value changed — for example, “Sales increased from 500 to 550” is a percentage change of 10%. The calculator can determine the result from the two values rather than requiring you to know the percentage in advance.

Percentage Difference

Percentage difference is useful when comparing two values without necessarily treating one value as the starting point. For two values, the percentage difference is commonly calculated using the absolute difference divided by the average of the two values.

For example, if two measurements are 80 and 100: difference = 100 − 80 = 20; average = (80 + 100) ÷ 2 = 90; percentage difference = 20 ÷ 90 × 100 ≈ 22.22%. Percentage difference is particularly useful when comparing measurements or values where neither number is necessarily considered the original value.

Markup vs. margin

Markup and Margin Aren’t the Same Thing

Markup and margin are frequently confused because both involve profit. However, they use different bases: markup is calculated from cost, while margin is calculated from selling price or revenue.

Suppose a product costs $100 and you apply a 50% markup. Markup: $100 × 50% = $50. Selling price: $100 + $50 = $150. The profit is $50. Now calculate the profit margin: $50 ÷ $150 × 100 = 33.3%. So a 50% markup produces a 33.3% margin.

This distinction is important for retailers, freelancers, small businesses, resellers, and anyone setting prices. Use the Markup calculator when you know your cost and want to determine a selling price. Use the Margin calculator when you know your revenue and cost and want to understand profitability.

Discounts and sale prices

Calculate Discounts Before You Buy

Percentage discounts are among the most common everyday uses of percentages. A store may advertise 20% off, 30% off, 50% off, or a 15% discount. To calculate a discount manually, multiply the original price by the discount percentage.

For example, a $120 product with a 25% discount: $120 × 0.25 = $30 discount; $120 − $30 = $90 final price. The discount calculator above can perform this calculation instantly, letting you determine: discount amount, final sale price, amount saved, percentage discounts, sale prices, and promotional pricing.

Remember that a discount percentage is normally applied to the original price unless the seller specifies another basis.

Tips, Taxes, VAT and Commission

The percentage-of-a-number calculator can be used for many calculations beyond traditional math exercises. For example, if your restaurant bill is $60 and you want to leave a 15% tip: $60 × 15% = $9.

Similarly, percentages can be used to estimate sales tax, VAT, service charges, tips, commission, fees, royalties, and bonuses. For example, a 5% commission on $2,000 is $2,000 × 0.05 = $100. The “% Of a Number” tool above can help you calculate these amounts quickly.

Salary and Income Percentage Calculations

Percentages are often used when comparing salary changes. Suppose your monthly salary increases from $2,000 to $2,300. The increase is $2,300 − $2,000 = $300. Percentage change: $300 ÷ $2,000 × 100 = 15%. So the salary increased by 15%.

You can also use the Percentage Increase tab when you already know the percentage increase — a salary of $2,000 with a 10% increase becomes $2,000 + $200 = $2,200.

If your income includes UK Share Incentive Plan contributions, our SIP Tax Savings Calculator shows exactly how much Income Tax and National Insurance a partnership share contribution saves at your own tax band. If you hold RSUs, ESPP shares, or stock options at a US company instead, see the US Equity Compensation Calculator to estimate their value after tax and FICA.

Business and Pricing Calculations

Percentage calculations are especially useful for small businesses and online sellers, who may need to calculate product markups, profit margins, sales discounts, commission rates, revenue changes, cost increases, price reductions, and promotional offers.

Suppose a product costs $80 to produce and you want a 25% markup. Markup: $80 × 25% = $20. Selling price: $80 + $20 = $100. If the product sells for $100, the $20 profit represents a 20% margin: $20 ÷ $100 × 100 = 20%. This example shows why choosing the correct calculator matters.

Shopping and Personal Budgeting

Percentages are useful when managing everyday spending. You can use the calculators above to compare sale prices, discounts, price increases, monthly expenses, budget changes, utility bills, subscription increases, and savings targets.

For example, if a monthly bill increases from $80 to $92: increase = $92 − $80 = $12; percentage increase = $12 ÷ $80 × 100 = 15%. This makes it easier to understand how significant a price increase actually is.

School, Homework and Study

Percentage problems are common in mathematics, economics, business studies, statistics, and other subjects. Students can use these calculators to check their work after solving a problem manually — finding percentages, converting percentages, calculating increases and decreases, comparing values, solving discount problems, working with profit and loss, and checking percentage changes.

For learning purposes, it is useful to understand the formula rather than relying only on the calculator. The formulas and examples on this page can help you understand how the calculations work.

Common mistakes

Common Percentage Mistakes

1. Forgetting to Divide by 100

A percentage such as 25% represents 25 ÷ 100, or 0.25. Incorrect: 25 × 200 = 5,000. Correct: 0.25 × 200 = 50.

2. Confusing Markup With Margin

A 40% markup does not mean a 40% profit margin. Markup is based on cost, while margin is based on revenue.

3. Using the Wrong Starting Value

Percentage change calculations depend on the reference or original value. For example, an increase from 100 to 120 is 20%. But a decrease from 120 to 100 is 16.67%, not 20% — the direction changes the base used in the calculation.

4. Assuming Equal Percentage Changes Cancel Out

A 20% increase followed by a 20% decrease does not return a value to its original amount. Starting with 100: a 20% increase gives 120; a 20% decrease from 120 gives 96. The final result is 96, not 100.

Reference

Percentage Conversion Reference

Converting between percentages, decimals, and fractions is another common percentage task. Some useful examples:

Percentage	Decimal	Fraction
10%	0.10	1/10
20%	0.20	1/5
25%	0.25	1/4
33.33%	0.3333	Approximately 1/3
50%	0.50	1/2
75%	0.75	3/4
100%	1.00	1

To convert a percentage into a decimal, divide by 100 — for example, 35% ÷ 100 = 0.35. To convert a decimal into a percentage, multiply by 100 — for example, 0.35 × 100 = 35%.

When Should You Use Each Calculator?

Choosing the correct calculator depends on what information you already have.

Use “% Of a Number” when you know a percentage and a number and want to find the corresponding amount. Example: What is 18% of 500?

Use “What Percent Of” when you know a part and a total and want to know what percentage the part represents. Example: 45 is what percent of 300?

Use “Percentage Increase” when you know the original value and the percentage increase. Example: Increase 800 by 15%.

Use “Percentage Decrease” when you know the original value and the percentage decrease. Example: Decrease 800 by 15%.

Use “Percent Change” when you know the original and new values and want to calculate the percentage change. Example: A price changes from $80 to $92.

Use “Discount” when you want to calculate a sale price after applying a discount. Example: What is the final price of a $150 item after 20% off?

Use “Markup” when you know your cost and want to add a markup to determine the selling price. Example: What should I charge if my cost is $80 and my markup is 30%?

Use “Margin” when you know revenue and cost and want to calculate the profit margin. Example: What is the margin when revenue is $200 and cost is $150?

Use “Reverse Percentage” when you know the final amount after a percentage change and want to find the original amount. Example: The final price is $120 after a 20% increase. What was the original price?

Your Calculations Run in Your Browser

The percentage calculators on this page are designed to perform calculations directly in your browser using JavaScript. The values you enter are not required to be sent to a server for the calculation itself. This means you can enter numbers, change them, and immediately see updated results without waiting for a server response. For the best experience, keep JavaScript enabled in your browser.

Quick Percentage Reference

Here are several common percentage calculations for quick reference: 1% of 100 = 1 · 5% of 100 = 5 · 10% of 100 = 10 · 15% of 100 = 15 · 20% of 100 = 20 · 25% of 100 = 25 · 30% of 100 = 30 · 40% of 100 = 40 · 50% of 100 = 50 · 75% of 100 = 75 · 100% of 100 = 100.

The same percentages can be applied to any number using the formulas above.

FAQ

Frequently Asked Questions

Start calculating

You don’t need a separate tool for every calculation

The Percentage Calculators Hub brings common percentage calculations together in one convenient place. Whether you’re checking a shopping discount, calculating a tip, comparing two values, determining a salary increase, setting a product markup, checking a profit margin, solving a homework problem, or working backwards from a final price, choose the calculator that matches your calculation and enter your numbers.

Scroll back up, enter your values, and get your percentage result instantly.