📈 Percentage Calculator

What is a Percentage Calculator?

A percentage calculator is a versatile math tool that solves all types of percentage problems instantly. Whether you need to find what percentage one number is of another, calculate percentage increase or decrease, or find the original value before a percentage change, our free online percentage calculator handles all these calculations with ease.

Common Percentage Calculations

• What is X% of Y? Answer = Y × X / 100. Example: 15% of 200 = 200 × 15/100 = 30
• X is what % of Y? Answer = (X/Y) × 100. Example: 45 is what % of 180? = (45/180) × 100 = 25%
• Percentage Increase: ((New − Old) / Old) × 100. Example: 50 to 75 = (25/50) × 100 = 50% increase
• Percentage Decrease: ((Old − New) / Old) × 100. Example: 100 to 80 = (20/100) × 100 = 20% decrease
• Original value before % increase: Original = New Value / (1 + %/100)

Percentage in Daily Life

Percentages are used everywhere in everyday life. When reading bank interest rates, understanding that 8% annual interest on a given deposit produces exactly 8% of that amount per year. When calculating exam scores — scoring 72 out of 90 = (72/90) × 100 = 80%. When calculating tips at restaurants — 15% of any bill amount, in any currency. When understanding tax rates, inflation, discounts, and commission percentages.

Percentage vs Percentile — What's the Difference?

A percentage expresses a ratio out of 100 — "you scored 85%." A percentile tells you what percentage of people scored below you — "you are in the 85th percentile" means 85% of people scored lower than you. Percentile is used in competitive exams like JEE, NEET, CAT, and UPSC to rank candidates against each other. A 99th percentile score means you outperformed 99% of all test takers.

Percentage Error and Accuracy

Percentage error measures how far an experimental or estimated value is from the actual (true) value. Formula: Percentage Error = |Experimental Value − Theoretical Value| / Theoretical Value × 100. For example, if you predicted monsoon rainfall would be 900mm but actual was 850mm: % error = |900 − 850| / 850 × 100 = 5.88%. Lower percentage error means higher accuracy.

The Different Types of Percentage Problems

Percentage calculations generally fall into a few distinct categories that require different approaches: finding what percentage one number is of another, finding a specific percentage of a given number, and finding the original number when a percentage of it is known. Confusing these categories, or applying the wrong formula variant to a given word problem, is one of the most common sources of percentage calculation errors, particularly in contexts like tips, discounts, and tax where the specific type of percentage question isn't always immediately obvious from how a problem is phrased.

Percentage change calculations — determining how much a value has increased or decreased in percentage terms — require using the original (starting) value as the denominator, not the new value, a distinction that becomes especially important and easy to get backward when working with prices, statistics, or financial figures that have changed significantly over time.

Percentage Points vs. Percentage Change

A frequently confused distinction: if an interest rate rises from 5% to 7%, that's an increase of 2 percentage points, but a 40% relative percentage increase (since 2 is 40% of the original 5). Financial and political reporting sometimes blurs this distinction, whether intentionally or not, and being able to correctly distinguish percentage points from percentage change is genuinely useful for accurately interpreting statistics presented in news and financial reporting.