Business Math

Select two numbers on any webpage to instantly calculate change, ratio, basis points, margin, markup, and more.

Business Math turns selected numbers into useful business calculations without making you open a calculator, spreadsheet, or AI chat. Select a first number on any webpage, save it from the right-click menu, then select a second number and compare them instantly. Core calculations: • Raw difference • Percentage change • Percentage difference • Ratio When both values are percentages: • Percentage-point change • Basis-point change Optional cost / price math: • Profit • Margin • Markup You can also click the Business Math toolbar icon to enter two values manually. Privacy-first by design: • No account required • No analytics • No browsing-history access • No selected values sent to a server • No host permissions • Calculations happen locally in your browser Business Math stores only the first value you explicitly save so it can be compared with the second value you select. That saved value remains on your device.