Percentage Calculator

Calculate percentages, increases, and decreases instantly.

1. What is X% of Y?

What is

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2. X is what percent of Y?

is what % of

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3. Percentage Change

Fromto

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How to Use

Select your calculation mode

Choose from: find X% of Y, find what % X is of Y, or calculate % change between two numbers.

Enter the required inputs

Fill in the two known numbers for your chosen mode. Decimals are supported.

Read the instant result

The percentage answer appears immediately with increase/decrease labeling for change calculations.

Apply to real-world scenarios

Use results for tips, discounts, grade calculations, sales growth, and data analysis.

How to calculate Percentages

Our completely free online percentage calculator allows you to quickly shift between percentage modes (X of Y, increases, and tracking decreases). Simply provide the two inputs and let our system solve the equation instantly.

Real-World Examples & Use Cases

Retail Discounts and Sale Pricing

Shoppers and retailers use percentage calculations constantly. A $120 jacket marked 35% off: 35% of $120 = $42 discount → sale price $78. A retailer applying a 22% markup to a $45 wholesale item: 22% of $45 = $9.90 → selling price $54.90. Layered discounts require sequential percentage calculations: a 20% discount followed by an additional 10% off is not a 30% total discount — it is 1 × (1-0.20) × (1-0.10) = 72% of original price, meaning a 28% effective discount.

Academic Grades and Test Scores

Students and teachers calculate percentage scores by dividing earned points by total possible points. Scoring 47 out of 60 on a test: 47/60 × 100 = 78.3%. Teachers computing weighted averages need percentage calculations at each step: a midterm worth 30% of the course grade and a final worth 40% require calculating each component as a percentage contribution to the total. Percentage calculators also help students understand how much their grade can change if they perform differently on remaining assessments.

Business Revenue and Growth Analysis

Business analysts track performance using percentage change. Revenue growing from $840,000 to $1,020,000: change = (1,020,000 - 840,000) / 840,000 × 100 = 21.4% growth. Profit margins: gross profit / revenue × 100. Market share: company sales / total market sales × 100. Year-over-year comparisons in reporting always use percentage changes to contextualize raw number differences — a $50,000 revenue increase means very different things for a $200,000 business versus a $5,000,000 business.

Nutrition and Health Tracking

Nutritional labels reference percentages of daily recommended values. A food containing 18g of fat when the daily reference is 65g: 18/65 × 100 = 27.7% of daily fat. Fitness goals often use percentages: losing 5% of body weight, staying below 25% of calories from fat, or hitting 80% of a protein target. Dieticians, fitness coaches, and individuals tracking macros use percentage calculations to measure progress and ensure nutritional guidelines are met across daily meal plans.

How It Works

Three core percentage formulas cover every use case: 1. Find X% of Y: Result = Y × (X / 100) Example: 15% of 80 = 80 × 0.15 = 12 2. X is what % of Y: Result = (X / Y) × 100 Example: 45 is what % of 180? → (45/180) × 100 = 25% 3. Percentage change from A to B: Result = ((B - A) / |A|) × 100 Positive = increase; Negative = decrease Example: from 250 to 310: ((310-250)/250) × 100 = 24% increase Example: from 400 to 320: ((320-400)/400) × 100 = -20% decrease Important: Percentage changes are not reversible. A 20% increase followed by a 20% decrease does NOT return to original: 100 × 1.20 × 0.80 = 96 (4% net decrease)

Frequently Asked Questions

What is the difference between percentage and percentage points?▼

These are commonly confused. Percentage change is a relative measure: if a rate goes from 5% to 8%, that is a 60% increase (3/5 × 100). Percentage points is an absolute measure: going from 5% to 8% is a 3 percentage point increase. In financial reporting, interest rate changes are typically described in percentage points (the central bank raised rates by 0.25 percentage points), while market returns are described as percentage changes (the index grew 12% this year).

How do I calculate a percentage of a percentage?▼

Multiply the percentages as decimals. 30% of 40% = 0.30 × 0.40 = 0.12 = 12%. This applies in contexts like: a product has a 30% chance of defect, and of those defects, 40% are critical — so 12% of all products have critical defects. Also used in probability calculations where independent events are combined by multiplication.

Why is a 50% increase not reversed by a 50% decrease?▼

Because the base changes between operations. Starting with 100: increase by 50% → 150. Decrease 150 by 50% → 75. Not back to 100. To reverse a percentage increase of X%, the required decrease is X/(100+X) × 100. To reverse a 50% increase: 50/150 × 100 = 33.3% decrease needed — not 50%. This asymmetry is critical in investment return calculations and business discount modeling.

How do I find the original price before a percentage discount?▼

Divide the discounted price by (1 - discount%). If a sale price of $68 reflects a 15% discount: original = $68 / (1 - 0.15) = $68 / 0.85 = $80. A common mistake is adding the discount percentage back to the sale price: $68 + 15% = $78.20 — which is wrong because the percentage is applied to the unknown original price, not to the discounted price.

How do I calculate compound percentage growth?▼

Compound growth applies percentage changes sequentially on the updated value: multiply the original by (1 + rate) for each period. 10% annual growth for 3 years: 100 × 1.10 × 1.10 × 1.10 = 133.1 (33.1% total growth, not 30%). For negative growth: 100 × 0.90 × 0.90 × 0.90 = 72.9 (27.1% total decline). This compounding effect is why investment returns and economic growth rates must be specified as annual compound rates for accurate comparison.

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