Percentage Calculator

Interactive Studio

Calculate what X% of Y is, what percent X is of Y, percentage increase or decrease, add/subtract percentages, and find original pre-discount values. Instant feedback with zero server storage.

Mode:

What is X% of Y?

Percentage (X%)

Total Value (Y)

Calculated Result

37.5

15% of 250 = 37.50

Math Formula:

(15 ÷ 100) × 250 = 37.50

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About Percentage Calculator

Percentages are used daily for taxes, tips, discounts, markups, and growth metrics. This studio handles all 5 essential percentage calculation scenarios with step-by-step mathematical explanations and real-time result formatting.

How to use Percentage Calculator

Pick the question you are asking: percent of a number, what percent one number is of another, or percentage change.
Fill in the two values for that question.
Read the result and the step-by-step working shown below it.

Worked examples

Input: What is 15% of 240?

Result: 36.

Input: 45 is what percent of 180?

Result: 25%.

Input: Change from 80 to 100

Result: A 25% increase. Going from 100 back to 80 is a 20% decrease, not 25%.

Background

Percent means per hundred. X% of Y is Y x X / 100. The share one number represents of another is part / whole x 100. Percentage change is (new - old) / old x 100.

Changes are measured against the starting value, so a rise and an equal-sized fall are not symmetric. A 50% increase followed by a 50% decrease leaves you 25% below where you started.

Common mistakes

Using the wrong base. Percentage change is always relative to the original value.
Confusing percentage points with percent. A rate moving from 4% to 6% is up 2 percentage points but up 50%.
Adding percentages from different bases.

Frequently Asked Questions

How is percentage increase/decrease calculated?

Using the formula: $\text{Percentage Change} = \frac{\text{New Value} - \text{Old Value}}{\text{Old Value}} \times 100$.

How do I find the original price before a discount?

Select 'Find Original Value', enter the discounted price and discount percentage. The formula used is $\text{Original} = \frac{\text{Final Price}}{1 - \frac{\text{Discount}\%}{100}}$.

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