Guides

Short, practical guides that explain the formulas and concepts behind each calculator. Written for business owners, freelancers, and anyone who wants to understand the math.

VAT Explained: What It Is, How It Works, and Who Pays It

A clear, practical guide to Value Added Tax — how it differs from sales tax, how it is calculated, and what businesses need to know about UK, EU, and international VAT rates.

Margin vs Markup: The Difference That Costs Businesses Money

Margin and markup both describe profit, but they are calculated differently. Confusing them leads to pricing errors. This guide clears it up with formulas, a conversion table, and examples.

How to Calculate Discount: Percentages, Stacking, and Reverse Calculations

Learn how percentage discounts work, how to calculate the final price, and why stacking discounts does not mean adding them together. Includes formulas for finding original prices.

Break-even Formula Explained: Fixed Costs, Variable Costs, and the Math

Understand the break-even formula, what contribution margin means, and how to find the exact point where your business starts making profit. Includes worked examples for retail and SaaS.