A free collection of online percentage calculators for everyday math: find what percent of a number, compute percentage increases and decreases, reverse a percentage change, and measure the percentage difference between two values. Every calculation runs locally in your browser — nothing is sent to a server.

Percentage Guide & Learning Hub

Understand the mathematics behind percentages, learn how they are calculated step-by-step, and explore practical examples for business, shopping, finance, and academics.

Basic Percentages (What is X% of Y?)

Overview

This is the most common percentage calculation. It finds the portion of a larger total representing a specific percentage. For example, if you want to know what a 15% tip on a $60 dinner bill is, you are looking for 15% of 60.

Formula Result = (X ÷ 100) × Y

How to Calculate Manually

  • Step 1: Convert the percentage (X) into a decimal by dividing it by 100: 15 ÷ 100 = 0.15.
  • Step 2: Multiply this decimal by the total value (Y): 0.15 × 60 = 9.
  • Step 3: Your result is 9.

Real-World Examples

Sales Tax / VAT: A store sells an item for $150. If the local sales tax is 8%, the tax amount added is (8 ÷ 100) × 150 = $12.

Credit Card Cashback: If a credit card offers 1.5% cashback on a purchase of $1,200, you will get back (1.5 ÷ 100) × 1200 = $18.

Finding the Percentage (X is what % of Y?)

Overview

This calculation determines what percentage a smaller portion (X) represents out of a whole total (Y). For example, if you scored 45 out of 50 on a test, what is your percentage grade?

Formula Percentage (%) = (X ÷ Y) × 100

How to Calculate Manually

  • Step 1: Divide the part (X) by the whole (Y): 45 ÷ 50 = 0.9.
  • Step 2: Multiply the result by 100 to format it as a percentage: 0.9 × 100 = 90%.

Real-World Examples

Academic Grading: Scoring 18 out of 24 points on a classroom quiz yields (18 ÷ 24) × 100 = 75%.

Fundraising Progress: A charity aiming to raise $5,000 has received $3,200 in donations. They have reached (3200 ÷ 5000) × 100 = 64% of their target.

Percentage Increase (X increased by Y%)

Overview

This adds a certain percentage of a starting value (X) onto itself. This is standard in calculating salary raises, asset growth, retail price markups, or inflation adjustments.

Formula Result = X × (1 + (Y ÷ 100))

How to Calculate Manually

  • Step 1: Convert the increase percentage (Y) to a decimal by dividing by 100: 10 ÷ 100 = 0.10.
  • Step 2: Add 1 to this decimal: 1 + 0.10 = 1.10 (this is the growth factor).
  • Step 3: Multiply the starting value (X) by this growth factor: $50,000 × 1.10 = $55,000.

Real-World Examples

Salary Raise: A worker earning $60,000/year gets a 5% raise. Their new salary is 60000 × (1 + 0.05) = $63,000.

Retail Price Markup: A wholesaler buys a watch for $40 and marks it up by 60% for retail sale. The customer price is 40 × (1 + 0.60) = $64.

Percentage Decrease (X decreased by Y%)

Overview

This subtracts a specific percentage of a starting value (X) from itself. It is widely used for retail sales discounts, stock portfolio losses, asset depreciation, or business budget cuts.

Formula Result = X × (1 - (Y ÷ 100))

How to Calculate Manually

  • Step 1: Convert the percentage drop (Y) to a decimal: 25 ÷ 100 = 0.25.
  • Step 2: Subtract this value from 1: 1 − 0.25 = 0.75 (this is the discount multiplier).
  • Step 3: Multiply the starting value (X) by this multiplier: $80 × 0.75 = $60.

Real-World Examples

Retail Discounts: A $120 winter coat is on sale with a 30% discount. The final price is 120 × (1 − 0.30) = $84.

Asset Depreciation: A new computer worth $1,500 depreciates in value by 20% in its first year. Its value drops to 1500 × (1 − 0.20) = $1,200.

Reverse Percentages (X is Y% more/less than what?)

Overview

This is used to find the original value of a number before a percentage change occurred. For example, if a jacket costs $115 after a 15% sales tax is added, what was the price before tax?

Formula Original = X ÷ (1 ± (Y ÷ 100))

Use + if the change was an increase, and if the change was a decrease.

How to Calculate Manually

  • Step 1: Convert the change percentage (Y) to a decimal: 15 ÷ 100 = 0.15.
  • Step 2: Adjust the factor based on the direction: for "more", add to 1 (1 + 0.15 = 1.15); for "less", subtract from 1 (1 − 0.15 = 0.85).
  • Step 3: Divide the final value (X) by this factor: 115 ÷ 1.15 = 100. The original price was $100.

Real-World Examples

Pre-Tax Subtotal: You paid $108 for a dinner that included an 8% sales tax. The pre-tax subtotal is 108 ÷ (1 + 0.08) = $100.

Original Price (Post-Sale): A clearance dress is marked down by 40% and is selling for $48. The original retail price was 48 ÷ (1 − 0.40) = $80.

Percentage Difference (Difference between A and B)

Overview

This measures the absolute difference between two numbers relative to their average. This symmetric metric is used when there is no clear "before" or "after" or "starting" value, such as comparing the populations of two cities or the prices of two different brands.

Formula Difference (%) = (|A - B| ÷ ((|A| + |B|) ÷ 2)) × 100

How to Calculate Manually

  • Step 1: Find the absolute difference: |80 − 100| = 20.
  • Step 2: Calculate the average of the two numbers: (80 + 100) ÷ 2 = 90.
  • Step 3: Divide the difference by the average and multiply by 100: (20 ÷ 90) × 100 ≈ 22.22%.

Real-World Examples

Product Comparison: Brand A's coffee costs $12 per bag, and Brand B's costs $15. The percentage difference between the two prices is (|12 − 15| ÷ ((12 + 15) ÷ 2)) × 100 = (3 ÷ 13.5) × 100 ≈ 22.22%.

Performance Benchmarks: Company A grows by 10%, while Company B grows by 15%. The percentage difference in growth performance is (|10 − 15| ÷ 12.5) × 100 = 40%.

Frequently Asked Questions

What is the difference between percentage change and percentage points?

A percentage change measures the relative difference between two values as a proportion of the original value (e.g., if an interest rate rises from 10% to 12%, that is a 20% increase in the rate). In contrast, percentage points measure the absolute difference between two percentages (e.g., rising from 10% to 12% is a 2 percentage point increase).

Can a percentage be greater than 100%?

Yes, a percentage can exceed 100%. This represents a value that is larger than the original whole or a growth that is more than double the starting point. For example, if a company's sales increase from $100 to $250, that represents a 150% increase, or 250% of the original sales.

How do you calculate percentages manually without a calculator?

To calculate a percentage manually, convert the percentage to a decimal by dividing by 100 (moving the decimal point two places to the left) and multiply by the target number. For example, to find 20% of 150, calculate 0.20 * 150, which equals 30. Alternatively, you can use fractional equivalents: 10% is 1/10th, 20% is 1/5th, 25% is 1/4th, and 50% is 1/2.

What is a reverse percentage and how is it used in finance?

A reverse percentage (or backward percentage) is a method used to find the original value of a number after a percentage increase or decrease has occurred. In finance, it is commonly used to find the price of an item before sales tax or VAT was added, or to determine the original investment amount before a market gain or loss.