Percentage Calculations Every Business Owner Needs to Master

Percentages appear in virtually every business metric: profit margin, revenue growth, conversion rate, discount pricing, tax, and performance targets. Getting them wrong leads to mispriced products, incorrect reports, and poor decisions.

The Four Essential Operations

X% of Y: What is 20% of £450? Answer: £90. For discounts, commissions, tips, and tax amounts. X is what % of Y: 45 of 180 customers converted — what is the rate? Answer: 25%. For rates and proportions. Percentage change: Measures growth or decline between two values. Apply a % increase or decrease: Calculates a new value after markup, markdown, or adjustment. The free Percentage Calculator handles all four modes with instant results.

Margin vs Markup: An Important Distinction

Markup is added to cost to arrive at price: a product costing £50 sold for £75 has a 50% markup. Margin is the percentage of sale price that is profit: the same example has a 33.3% margin. Confusing these erodes profitability without warning — a 50% markup is not the same as a 50% margin.

VAT and Tax Calculations

To add tax to a pre-tax price, use Increase by % mode. To find the pre-tax price from a tax-inclusive amount, divide by (1 + tax rate/100) — do not simply subtract the percentage. Backing out 20% VAT from £120 gives £100, not £96. Getting this wrong creates accounting errors that compound over time.