Guide

Percentage Decrease Calculator 2025: Find Discounts & Drops (Free)

January 17, 2025
11 min read
By Tools Team

In a world of sales, discounts, and fluctuating markets, understanding percentage decrease is essential. Whether you are a shopper trying to figure out how much you'll save on a deal, or a business owner analyzing a drop in sales, knowing how to calculate the decline is key to making smart decisions.

This guide will explain exactly what percentage decrease is, provide the formula you need, and walk you through practical examples so you can calculate it with confidence.

What is Percentage Decrease?

Percentage decrease measures the reduction in value of a variable, expressed as a percentage of its original value. It answers the question: "How much smaller is this number now compared to what it used to be?"

  • Discounts: "20% off" means the price has decreased by 20%.
  • Depreciation: How much value a car loses over time.
  • Weight Loss: Tracking progress in a fitness journey.
  • Business Metrics: Analyzing drops in revenue or customer retention.
The Percentage Decrease Formula

Percentage Decrease = ((Original Value - New Value) / Original Value) × 100

Original Value: The starting number (must be larger).

New Value: The ending number (must be smaller).

Difference: The amount lost or reduced.

Step-by-Step Calculation Guide

Scenario: Buying a Laptop on Sale

A laptop was originally priced at $1,000, but it is now on sale for $800.

  1. Find the Difference: $1000 - $800 = $200
  2. Divide by Original: $200 / $1000 = 0.20
  3. Convert to %: 0.20 × 100 = 20%

Result: The laptop is 20% off.

Real-Life Examples

Car Depreciation

Bought: $30k | Now: $24k

20% Value Loss

Weight Loss

Start: 200lbs | Now: 180lbs

10% Body Weight

Energy Efficiency

Old Bill: $150 | New: $90

40% Savings

Health & Fitness Goals

Tracking weight loss? Don't forget to check your BMI to ensure you are in a healthy range.

Frequently Asked Questions

How do I calculate a 20% decrease?

To decrease a number by 20%, multiply it by 0.80 (since 100% - 20% = 80%). Example: 50 × 0.80 = 40.

What is the difference between percentage decrease and percentage change?

Percentage decrease is a specific type of percentage change where the value goes down. Percentage change covers both increases and decreases.

Is a 50% decrease the same as dividing by 2?

Yes! Decreasing a number by 50% is exactly the same as cutting it in half.