Business & Tax
Updated August 5, 2026
Running a business or side hustle means pricing, taxing, and forecasting correctly. This hub organizes every PraxisCalc business calculator and guide in one place, from finding your break-even point to calculating sales tax.
Your break-even point tells you how many units you need to sell to cover costs. Profit margin and markup calculators help you price for sustainable profitability.
Units, sales revenue & breakeven point
Gross, net & percentage margin
Retail price & markup percentage
Sale price, percent off & final cost
Sales tax rules and cash-flow health both directly affect how a business prices products and survives slow periods.
Calculate sales tax
Check your liquidity ratio
Future purchasing power
Live foreign exchange rates
Marketplace fees eat directly into margin on every sale, so it pays to model them before you price a listing.
Start with the break-even or profit margin calculator to check your pricing, then use the tax and working capital tools to make sure the business can sustain that pricing month to month.
Each guide answers one pricing or costing question directly, shows the formula, and works a real example through to the answer.
The markup formula, working out selling price from cost, and why markup is not the same as margin.
Gross and net margin, pricing to a target margin, and the mistake that quietly underprices every sale.
Break-even in units and in sales dollars, contribution margin, and pricing for a target profit.
Percent off, stacked discounts, adding sales tax, and reversing a sale price to the original.
Removing tax from an inclusive price, adding it to a net price, and why subtracting the percentage fails.
Stacking commission, payment processing and listing costs to find what you actually keep on a sale.
The formula, the ratio, and why a profitable business can still run out of cash.
Converting between currencies and spotting the margin providers add to the mid-market rate.