Tools
Financial calculators
Each tool runs in your browser, shows its method, and cites its sources. Start with markup; more are on the way.
Markup Calculator
Selling price from cost and markup.
OpenBusiness Days Calculator
Deadlines and due dates, holidays included.
OpenInterest Calculator
Simple and compound interest per period.
Coming soon Spreadsheet template
Get the pricing template
Markup spreadsheet: cost → price, markup vs. margin, multiple items.