Guide

How to Calculate Percentage in 2025: Ultimate Guide (5 Easy Methods)

January 15, 2025
10 min read
By Tools Team

Percentages are everywhere. From calculating discounts during a sale to determining the tip at a restaurant, or analyzing financial growth in business, understanding how to calculate percentage is an essential life skill. Yet, for many, the concept can still feel a bit daunting.

If you’ve ever found yourself asking, "What is the percentage of this number?" or "How do I calculate percentage increase?", you are in the right place. This ultimate guide will walk you through everything you need to know about percentages, including the basic formulas, real-life examples, and how to use online tools to make the process instant.

What is a Percentage?

At its core, a percentage is a number or ratio expressed as a fraction of 100. The word comes from the Latin phrase per centum, which literally means "by the hundred." It is denoted using the percent sign, "%".

Think of it this way: if you have 100 apples and 30 of them are red, then 30% of your apples are red. It’s a standardized way of comparing quantities, regardless of the total amount.

The Basic Percentage Formula

Percentage = (Part / Whole) × 100

Part: The portion of the whole you are focusing on.

Whole: The total amount.

100: The multiplier that converts the decimal into a percentage.

How to Calculate Percentage of a Number

Often, you need to find a specific percentage of a total number. For instance, "What is 20% of 150?"

Real-Life Example: Calculating a Tip

You are at a restaurant, and the bill is $80. You want to leave a 15% tip.

  1. Percentage: 15% → 0.15
  2. Total: $80
  3. Calculation: 0.15 × 80 = 12

You should leave a $12 tip.

Percentage Increase

Crucial for tracking growth, like salary raises or traffic stats.

((New - Old) / Old) × 100

Example: Salary goes from $50k to $55k.
($5k / $50k) × 100 = 10% raise.

Percentage Decrease

Used for calculating discounts and losses.

((Old - New) / Old) × 100

Example: $200 jacket on sale for $150.
($50 / $200) × 100 = 25% off.

Check Your Health Metrics

Percentages are also used in health, like body fat percentage. While BMI isn't a percentage, it's a vital health metric.

Frequently Asked Questions

How do I calculate a percentage between two numbers?

To find the percentage of one number (X) in relation to another (Y), divide X by Y and multiply by 100. Formula: (X / Y) × 100.

How do I take 20% off a price?

Multiply the original price by 0.80 (which represents the remaining 80%). Or calculate 20% and subtract it.

How do I calculate percentage on a calculator?

Most calculators have a % button. To find 15% of 200: Type 200, press x, type 15, press %. The result 30 will appear.