Percentage Decrease Calculator

Calculate percentage decrease from an original value to a lower new value, with decrease amount and step-by-step formula.

946.1K uses Updated · 2026-05-09 Runs locally · zero upload
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How to Use Percentage Decrease Calculator

The Percentage Decrease Calculator measures how much a value dropped relative to its original baseline. Enter the original value, the new value, and the preferred decimal places. The result panel shows the percentage decrease, decrease amount, and the formula steps.

Use this tool when the new value is lower than the original value. If the new value is higher, the calculator gives a clear message because that case is a percentage increase instead.

Formula & Theory - Percentage Decrease Calculator

The Percentage Decrease Calculator uses the decrease formula.

percentage decrease = ((original value - new value) ÷ original value) × 100%

For example, if a price drops from 100 to 80, the decrease amount is 20, and the percentage decrease is 20%.

Use Cases for Percentage Decrease Calculator

Use the Percentage Decrease Calculator for discounts, price drops, cost reductions, lower traffic, declining inventory, grade changes, and comparing before-and-after measurements where the value goes down.

Frequently asked questions about Percentage Decrease Calculator

What if the new value is larger?

The calculator explains that the input is not a decrease, because the new value is greater than the original value.

Why can original value not be zero?

The formula divides by the original value, so a zero baseline cannot be used.

Is my data stored?

No. All calculations happen in your browser; nothing is sent to a server.