GridCalc: An RPN Spreadsheet for iOS

I built GridCalc because spreadsheets on phones feel fundamentally wrong.

On desktop, spreadsheets work because you can see formulas, references, and structure all at once. On mobile, that collapses. You’re constantly panning, zooming, tapping small cells, and losing context.

RPN (Reverse Polish Notation) removes parentheses and operator precedence by using a stack. Instead of writing = (a + b) * c, you enter a b + c *. The order of operations is explicit and linear.

GridCalc combines those ideas: a visible RPN stack with a reference grid.

It’s built for quick, ad-hoc modeling on a phone: loan calculations, position sizing, cash flow scenarios, engineering back-of-napkin math.

It’s not trying to replace Excel. It’s trying to make mobile calculation feel native instead of cramped.

Happy to answer questions about design decisions or implementation.