Free Percentage Calculator – Calculate % Change, X% of Y, Increase & Decrease

Work out percentage increase/decrease, find X% of Y, or see what percent one number is of another. Fast, accurate, and mobile-friendly.

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⚠️ Advisory only: Results are for guidance. For tax, finance, grades or contracts, confirm with a qualified professional or official source.

Cinematic 3D illustration of a man holding a calculator showing “59%”, with floating icons for pie chart and percentage increase, promoting a free percentage calculator.

Percentage Calculator

Known value or leave blank if solving for Part.
Known value or leave blank if solving for Whole.
Known value or leave blank if solving for Percent.
Reset

Your result will appear here

Enter two known values and choose what to find.

Why use this Percentage Calculator?

Multiple modes

X% of Y • What % is X of Y • % increase/decrease • % difference.

Smart rounding

Control decimal places and see exact math.

Step-by-step breakdown

We show the formula and each calculation step.

Shareable

Copy a link that preserves your inputs and result.

How to Use the Percentage Calculator: Step-by-Step Guide

1

Choose a mode

e.g., % change, X% of Y.

2

Enter your numbers

Use decimals if needed.

3

Read the result

Plus a step-by-step breakdown.

Why Use Our Percentage Calculator? Key Features & Benefits

  • Choose the correct mode (don’t mix % change with “what percent of”).
  • Enter positive values for most tasks; negative values can model decreases.
  • Adjust decimal places to match your context (money, grades, etc.).
  • For finance/tax decisions, always confirm with official guidance.

Understanding Percentage Math: What You Need to Know

A percentage is a ratio “per hundred.” Common tasks include finding a portion of a value, reversing the calculation to find what percent one number is of another, and measuring the relative change between two values. This tool handles all three with clear formulas and a worked breakdown.

Formulas Explained with Worked Examples

  • X% of Y: result = (X / 100) × Y
  • What percent is A of B? percent = (A / B) × 100%
  • % increase from Old to New: ((New − Old) / Old) × 100%
  • % decrease from Old to New: ((Old − New) / Old) × 100%
  • % difference between A and B (symmetric): (|A − B| / ((A + B)/2)) × 100%

Worked example: Price was £80, now £92 → % increase = ((92 − 80) / 80) × 100% = 15%. Another example: 25% of 140 = (25/100) × 140 = 35.

Rounding: Money usually to 2 decimals; grades might use 1; engineering results may need more.

Frequently Asked Questions About Percentages

% change is relative (e.g., 10% rise). Percentage points are absolute differences between percentages (e.g., 30% to 35% = +5 percentage points).

Yes. Decimals are supported. Negative values can model decreases or deficits where appropriate.

Division by zero is undefined. Enter a non-zero comparison value for B.

No. The calculator computes the exact value, then rounds for display. You can change decimal precision.

Discounts, VAT, ROI, grade changes, survey results, KPIs, interest rates, and more.

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What Our Clients Say About Our Calculators

Overall Rating
5.0/5 3 reviews
Priya

This estimator feels like a mini financial advisor. It’s incredibly helpful for first-time buyers to understand their limits. The income-to-debt ratio logic is spot on.

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Dhruv

This tool is a lifesaver for budgeting. It’s intuitive and gives a clear breakdown of monthly payments. I especially like the amortization summary—it’s great for planning long-term.

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Rohan

Simple, fast, and accurate. The BMI Calculator gives instant results with clear health categorization. I appreciate the clean layout and mobile responsiveness—it’s perfect for quick checks on the go

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Information on this page is for education only and is not a substitute for professional financial or tax advice.