Percentage Calculator
Calculate percentages three ways: find what a percentage is worth, express one value as a percentage of another, or work backwards to find the whole. Essential for pricing, tax, discounts, margins, and business analysis.
Quickly calculate percentages three ways: find what a percentage is worth, express one value as a percentage of another, or work backwards to find the whole amount. Essential for pricing, taxes, discounts, margins and business analysis.
Formula
What is X% of Y? = Y × (X ÷ 100) | X is what % of Y? = (X ÷ Y) × 100 | X is Y% of what? = (X ÷ Y) × 100
The first formula calculates a percentage value from a base amount — used to find discount amounts, tax, or portion calculations. The second expresses one value as a percentage of another — used for margin, ROI, or growth calculations. The third works backwards from a known part and percentage to find the whole — used for pricing, cost calculations, or reverse commission.
Worked Examples
Example 1: What is 20% of $150? (Price discount)
Result = $150 × (20 ÷ 100) = $30.00
Example 2: $30 is what % of $150? (Margin check)
Result = ($30 ÷ $150) × 100 = 20%
Example 3: $30 is 20% of what? (Cost from margin)
Result = ($30 ÷ 20) × 100 = $150.00
Common Mistakes
- 1.Not dividing by 100 when calculating percentages. "20% of 150" is NOT 20 × 150 = 3000. You must divide: 150 × (20 ÷ 100) = 30. Always convert percentage to decimal form first.
- 2.Confusing part and whole in percentage calculations. "30 is what % of 150?" is (30 ÷ 150) × 100 = 20%, NOT (150 ÷ 30) × 100. The smaller number goes on top unless you're finding the whole amount.
- 3.Adding percentages instead of multiplying them sequentially. Two 20% discounts in a row = original × 0.80 × 0.80 = 64% of original (36% total discount), NOT 40% off. Percentages are multiplicative, not additive.
- 4.Treating "X% more" as just adding X%. "20% more than 100" is 100 + (100 × 0.20) = 120. It's the original amount PLUS the percentage of the original, not just the percentage value.
Frequently Asked Questions
Use this in your workflow
After calculating a percentage, use the Margin Calculator to check whether a discounted price or commission cost still delivers your required profit margin. Use the Discount Calculator to apply percentage discounts to full prices, or the VAT Calculator to add tax percentages. Browse all Free Business Calculators.
When to use this calculator
- →Finding the discount amount or final price by calculating what a percentage is worth in currency
- →Checking gross profit margin by expressing net profit as a percentage of total revenue
- →Calculating commission earned, tax owed, or VAT payable as a percentage of transaction value
- →Working backwards from a cost to find the original price at a given markup or margin percentage
- →Analyzing growth rates, comparing values, or converting between percentages and actual amounts
How percentages work in three modes
Each mode solves a different business problem.
Mode 1: What is X% of Y?
Find the percentage value — used for calculating discount amounts, tax owed, commission earned, or portions of a total. Example: What is 20% of $150? Answer: $30. Formula: $150 × (20 ÷ 100) = $30.
Mode 2: X is what % of Y?
Express one value as a percentage of another — used for checking margins, calculating ROI, analyzing budget spend, or verifying tax rates. Example: $30 is what % of $150? Answer: 20%. Formula: ($30 ÷ $150) × 100 = 20%.
Mode 3: X is Y% of what?
Work backwards to find the whole amount — used for reverse pricing (finding list price from cost and markup %), recovering original amounts from percentages, or calculating the base from a margin. Example: $30 is 20% of what? Answer: $150. Formula: ($30 ÷ 20) × 100 = $150.
Business use cases
Pricing & Discounts
Calculate 15% promotional discount on a $200 product. Mode 1: What is 15% of $200? = $30. Final price: $170.
Profit Margins
Check margin on a sale. Mode 2: $40 profit is what % of $200 sale? = 20% gross margin. Helps you verify pricing strategies.
Tax & VAT
Calculate tax on a transaction. Mode 1: What is 20% VAT on $500? = $100. Total with tax: $600.
Commission & Fees
Determine commission. Mode 1: What is 10% commission on a $5,000 sale? = $500 earned.
Reverse Pricing
Find cost from margin. Mode 3: $50 is my 25% margin target of what? = $200 list price. Set prices correctly.
Growth & Change
Analyze growth. Mode 2: Revenue grew $50k against $200k baseline. That's what %? = 25% growth year-over-year.