Percentage Calculator

The percentage calculator handles three of the most common percentage problems in one tool: finding what X% of a number is, calculating percentage change between two values, and increasing or decreasing a number by a percentage. No formula recall required — just enter the numbers and get an instant answer. It is useful in far more situations than most people expect. Shoppers use it to verify a 30%-off discount before heading to the register. Students use it to convert raw scores to grade percentages. Professionals use it to calculate salary increase offers, mark up supplier pricing, or figure out how much a budget has grown year-over-year. Investors use it to check portfolio returns and compare rate changes. The calculator covers all three directions of percentage arithmetic. Forward (what is 15% of $240?), reverse (what percentage is $36 of $240?), and change (what is the percentage increase from $200 to $240?). Each question requires a different formula, so having all three in one place saves the mental overhead of figuring out which method applies.

How to Use the Percentage Calculator

The Percentage Calculator is designed to give you an accurate answer in seconds. Follow these steps:

1. Step 1: Choose the type of percentage calculation you need — "What is X% of Y?", "What percentage is X of Y?", or "Percentage change from A to B".
2. Step 2: Enter the numbers into the fields for your chosen mode. For example, to find 15% of $240, enter 15 in the percentage field and 240 in the number field.
3. Step 3: Your result appears instantly below the inputs. Switch to a different mode at any time to run a different type of calculation without clearing your numbers.

No account or sign-up required. All calculations run locally in your browser — nothing is stored or transmitted to any server.

How It Works

X% of Y = Y × (X ÷ 100) | % Change = ((New − Old) ÷ Old) × 100

Three separate formulas power the three calculation modes: 1. Percentage of a number: Result = Number × (Percentage ÷ 100) Example: 15% of 80 = 80 × 0.15 = 12 2. Percentage change between two values: Change = ((New − Old) ÷ Old) × 100 Example: from 200 to 250 = ((250 − 200) ÷ 200) × 100 = 25% increase 3. Increase or decrease by a percentage: Result = Original × (1 ± Percentage ÷ 100) Example: $500 increased by 12% = 500 × 1.12 = $560 A common mistake is confusing percentage change with percentage points. If an interest rate rises from 3% to 5%, it has increased by 2 percentage points but by 66.7% in percentage terms. The distinction matters enormously in financial reporting and academic writing — use this calculator to check which measure is appropriate for your context. For discount calculations, the most reliable method is to apply the percentage directly: a 20% discount on a $75 item equals $75 × 0.20 = $15 off, giving a final price of $60. Cross-check by asking: 80% of $75 = $75 × 0.80 = $60. Both routes should give the same answer.

Frequently Asked Questions