Math

Instant, private, and free

Percentage Calculator.

Calculate percentages, increases, decreases, and percentage changes

On-device calculationNo signup
01

Set your values

Results update as you type.

Calculation Type

How to Use

Basic: Calculate X% of Y

Of: Find what percentage X is of Y

Change: Calculate percentage change from X to Y

Increase/Decrease: Increase or decrease X by Y%

FAQs

How do I calculate what percentage A is of B?

Divide A by B and multiply by 100: (A ÷ B) × 100 = Percentage.

How do I calculate percentage increase or decrease?

Subtract the old value from the new value, divide by the old value, and multiply by 100.

Cite this calculator

Canonical URL: https://mathify.one/en/math/percentage

Cite as: Mathify. (2026). Percentage Calculator. https://mathify.one/en/math/percentage

Use Cases

Everyday Shopping Discounts

Quickly determine sale prices or savings when a discount percentage is applied to an item's original price.

Example: A $50 item with 25% off costs $37.50.

Financial and Business Analysis

Calculate percentage increases or decreases in revenue, expenses, or other metrics to assess performance.

Example: Sales rose from $10,000 to $12,500, a 25% increase.

Frequently Asked Questions

How do I calculate a percentage of a number?
Enter the percentage and the number. The calculator multiplies the number by the percentage (divided by 100) to give you the result. For example, 20% of 150 is 30.
How do I calculate percentage increase or decrease?
Input the original value and the new value. The calculator computes the difference, divides by the original, and multiplies by 100 to show the percentage change. A positive result indicates an increase, negative a decrease.
Can this calculator find the percentage change between two numbers?
Yes, it calculates the percentage change by comparing the difference to the original number. This is useful for tracking growth, price changes, or performance over time.

Tips & Common Mistakes

Tips

  • Double-check that you enter the percentage as a number (e.g., 25) not a decimal (0.25) unless you intend to use decimal form.
  • For percentage change, ensure you input the original value as the base, not the new value, to get the correct direction.
  • Use the calculator to verify manual calculations, especially when dealing with large numbers or multiple steps.
  • Remember that a percentage decrease is represented as a negative change; interpret the sign accordingly.

Common Mistakes to Avoid

  • Confusing percentage points with percentage change: a rise from 10% to 15% is a 50% increase, not 5%.
  • Entering the new value as the original when calculating percentage change, leading to an inverted result.
  • Forgetting to convert a percentage to a decimal when doing manual calculations, but this calculator handles it for you.

Last updated: August 13, 2026