What is the Percent Calculator?

The Percent Calculator is a free online tool that helps you calculate results instantly. Enter your values above and click Calculate to see results.

Is the Percent Calculator free?

Yes, the Percent Calculator is completely free to use with no registration required. You can use it as many times as you need on any device.

How accurate is this calculator?

Our Percent Calculator uses standard formulas for accurate results. For critical decisions, always verify with a qualified professional.

Percent Calculator

Three ways to calculate percentages. Find the percentage of a number, determine what percent one number is of another, or find the whole from a percentage.

3 Ways to Calculate Percentages

Percentage (X %)

Of this number (Y)

Formula: Result = (X / 100) × Y

Part (X)

Whole (Y)

Formula: Percentage = (X / Y) × 100

Part (X)

Is this % (Y)

Formula: Whole = X / (Y / 100)

Percentage Formulas

What is X% of Y? Answer = Y × (X/100)

X is what % of Y? Percent = (X/Y) × 100

X is Y% of what? Whole = X ÷ (Y/100) = X × (100/Y)

Percentage increase: ((New − Old) / Old) × 100

Percentage decrease: ((Old − New) / Old) × 100

Frequently Asked Questions

For quick mental math: 10% = move the decimal point one place left. 1% = move two places left. 5% = half of 10%. 25% = divide by 4. 50% = divide by 2. For example, 15% of 80: find 10% (= 8), find 5% (= 4), add them: 12. For more complex percentages, use our calculator above for instant accurate results.

"Percent" (using the % symbol) is used with a specific number: "15 percent" or "15%". "Percentage" is a more general term used without a specific number: "a large percentage of people." In everyday speech these terms are used interchangeably, but technically, "percent" means "per hundred" (from Latin per centum), always referring to a specific rate, while "percentage" refers to the overall concept or a general part of a whole.

How Percentage Calculations Work

Percentages express a number as a fraction of 100. They're used everywhere: discounts, tax rates, tip amounts, grade scores, growth rates, and financial returns. The key is knowing which type of percentage you're calculating — percentage of a value, percentage change, or percentage difference — because each uses a different formula.

The Core Formulas

X% of Y: (X / 100) × Y — Example: 20% of $85 = $17
What % is X of Y: (X / Y) × 100 — Example: 17 is what % of 85? = 20%
Percentage change: ((New − Old) / Old) × 100 — Example: from $80 to $100 = +25%
Percentage difference: |A − B| / ((A + B) / 2) × 100 — symmetric comparison
Percentage off (discount): Original price × (1 − discount rate) — Example: $80 at 25% off = $60

How to Use This Calculator

Enter the values you want to compare or calculate
Select the type of percentage calculation if prompted
Click Calculate for your result and the step-by-step working

Common Mistakes

Percentage increase vs. percentage points: A rate going from 5% to 8% is a 3 percentage point increase, but a 60% percentage increase. These are not the same thing, and confusing them is extremely common in news coverage.

Percentage off vs. percentage of original: "30% off $200" = $140 (you pay 70% of $200). "Pay 30% of $200" = $60. Read the phrasing carefully.