How do I find a percentage of a number?

Use "X% of Y" mode. Enter the percentage (X) and the number (Y). The result is (X / 100) × Y.

How do I calculate percent change?

Use "% change from X to Y" mode. The formula is ((Y − X) / |X|) × 100. A positive result is an increase; negative is a decrease.

Can I enter negative numbers?

Yes. All modes support negative and decimal numbers.

How is "Add X% to Y" calculated?

The result is Y × (1 + X / 100). For example, 150 + 10% = 150 × 1.10 = 165.

What does "X is what % of Y" return?

It returns (X / Y) × 100. For example, 30 is what % of 150 = 20%.

Percentage Calculator

Name: Percentage Calculator
Availability: InStock
Author: Nham Vu

Choose a mode, enter two values, and get the result instantly.

Calculation Settings

Mode

X% of Y

e.g. 20% of 150 = 30

X is what % of Y

e.g. 30 is what % of 150?

% change from X to Y

e.g. from 100 to 120 = 20% increase

Add X% to Y

e.g. 150 + 10% = 165

Value X (%)

Value Y

Results

Real-time calculation

Enter values on the left to see results instantly.

Supports decimals and negative numbers.

Summary

Choose a mode, enter two values, and get the result instantly.

How it works

Select a calculation mode from the left panel.
Enter both values in the input fields.
The result updates instantly with explanation.
Click Reset to clear all values.

Use cases

Calculate a discount: what is 20% of $150?
Find what percentage a score is out of total marks.
Calculate price change percentage between two periods.
Add sales tax or tip to a base amount.

Frequently Asked Questions

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Last updated: 2026-06-03 · Reviewed by Nham Vu