📊 Percentage Calculator

Three powerful percentage calculation modes in one tool. Find percentages, percentage differences, and percentage changes instantly.

Percentage Calculator

Mode 1: What is X% of Y?

% of

Mode 2: X is what % of Y?

out of

Mode 3: Percentage Change from X to Y

→

The Complete Guide to Percentage Calculations

Percentages are one of the most universally useful mathematical concepts in everyday life. From calculating discounts while shopping, to understanding interest rates on loans, to interpreting statistics in news reports, to grading academic performance — percentages appear constantly. Yet many people struggle to quickly perform percentage calculations mentally or even with a standard calculator.

UltraTools Percentage Calculator offers three distinct calculation modes to cover the most common percentage problems:

  • Mode 1 – Find a Percentage of a Number: "What is 15% of $200?" → $30
  • Mode 2 – Find What Percentage One Number is of Another: "45 is what % of 180?" → 25%
  • Mode 3 – Calculate Percentage Change: "The price changed from $80 to $100, what's the % increase?" → 25%

Percentage Formulas Explained

Formula 1 (X% of Y): Result = (X ÷ 100) × Y

Formula 2 (X is what % of Y): Result = (X ÷ Y) × 100

Formula 3 (% change from A to B): Result = ((B − A) ÷ |A|) × 100

Common Real-World Applications

Shopping and Discounts

The most familiar percentage use case: finding the final price after a percentage discount. If a $249 jacket is 30% off, you pay 70% of $249 = $174.30. Our Discount Calculator handles this with one input.

Academic Grades

Converting raw scores to percentages: scoring 42 out of 50 = (42/50) × 100 = 84%. This is Mode 2 of our calculator.

Financial Growth

Investment returns, salary increases, and inflation are all expressed as percentage changes. If your portfolio grew from $10,000 to $11,500, that's a 15% gain.

Tip Calculations

A 20% tip on a $65 restaurant bill = (20/100) × 65 = $13. Total with tip: $78.

Frequently Asked Questions

Percentage points and percentages measure different things. If an interest rate rises from 2% to 5%, that is an increase of 3 percentage points, but it is a 150% increase in the rate itself. This distinction matters enormously in finance and statistics. Percentage points express absolute differences between percentages; percentage change expresses relative differences.
Yes, absolutely. Percentages greater than 100% indicate that a value is more than the reference value. For example, if a product's price doubles, it increases by 100%. If it triples, it increases by 200%. Growth rates for rapidly growing companies or investments frequently exceed 100%.
Use Mode 1: enter the tip percentage (e.g., 20) and the bill amount (e.g., 85). The result is the tip amount ($17). Add it to the original bill for the total. For quick mental math, a 20% tip is simply double the 10% tip — move the decimal one place left, then double it.