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Percentage Calculator

100% Client-Side

Solve percentage questions: What is X% of Y, X is what % of Y, percentage increase/decrease, and add/subtract percentages with step-by-step math.

1. What is X% of Y?

What is % of = 12

2. X is what percent of Y?

is what % of = 25%

3. Percentage Increase / Decrease from X to Y

From to = +50.00% (Increase)

4. Add or Subtract X% to/from Y

% = 132.00

How to Use Percentage Calculator

Choose Equation Mode

Select from What is X% of Y, Percent Difference, or Add/Subtract %.

Enter Numbers

Input your values and observe instantaneous results as you type.

Copy Result

Grab calculated solutions directly into your clipboard.

✓ 4 Common Percentage Tasks

Covers discounts, markups, percent changes, and fraction ratios in one screen.

✓ Step-by-Step Formula

Shows the algebraic formula used to compute the answer.

✓ Zero Latency

Computes in real-time on every keystroke.

🔒 Complete Client-Side Isolation

This tool runs entirely in your local browser runtime. No logs, analytics tracking, or remote server transmissions occur.

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