CalcBase – Business Calculators

Percentage Calculator

Three percentage modes in one tool: find what X% of any number equals, calculate what percentage one value is of another, or work backwards to find the original total when you know the part and the rate. Every result shows the formula so you can verify the math.

Formula

Amount = Total × (Percent ÷ 100)
Percent = (Part ÷ Total) × 100
Whole = Part ÷ (Percent ÷ 100)

All three percentage calculations use the same relationship: Percent × Total = Part × 100. Rearrange for what you need: to find the amount multiply total by the rate; to find the rate divide part by total; to find the whole divide part by the rate.

Worked Examples

What is 15% of $200?

A sales rep earning a 15% commission on a $200 sale.

Percent
15%
Total
$200

15% of $200 = $30.

45 is what percent of 180?

A business made $45 profit on a $180 sale — what is the margin?

Part
45
Total
180

45 is 25% of 180.

30 is 12%, what is the whole?

A discount of $30 represents 12% off — what was the original price?

Part
$30
Percent
12%

The whole = $250.

Frequently Asked Questions

How do I calculate a percentage of a number?▾

Multiply the number by the percentage divided by 100. For example, 15% of 200 = 200 × 0.15 = 30. This works for any percentage and any number.

How do I find what percentage one number is of another?▾

Divide the part by the whole, then multiply by 100. For example, 45 out of 180 = (45 ÷ 180) × 100 = 25%. This is also the formula for profit margin when part is profit and whole is revenue.

How do I find the original number before a percentage was taken?▾

Divide the known part by the percentage rate (as a decimal). If 30 represents 12% of something: 30 ÷ 0.12 = 250. This is the reverse percentage calculation.

What is the difference between percentage and percentage points?▾

A percentage is a proportion of a total. A percentage point is the arithmetic difference between two percentages. If a rate goes from 10% to 15%, it increased by 5 percentage points, but by 50% as a relative change.

How do I calculate percentage increase or decrease?▾

Use the Percentage Change Calculator for increases and decreases. The formula is: ((new − old) ÷ old) × 100. A positive result is an increase; a negative result is a decrease.

Related Calculators

Percentage Change Calculator

Calculate the percentage increase or decrease between two numbers, or find the new value after applying a percentage change.

Discount Calculator

Calculate the discount amount and final price after applying a percentage discount.

Margin Calculator

Calculate profit margin from revenue and cost. See profit and margin percentage.

Markup Calculator

Calculate markup percentage from cost and selling price, or find the selling price from a target markup.

ROI Calculator

Calculate return on investment. See your ROI percentage and net profit instantly.

All calculations are for informational purposes only. They should not replace professional financial, tax, or legal advice. Always consult a qualified professional for decisions affecting your finances or business.