One of the typical challenges when exporting numerical computations is how to include the way the calculations were achieved. Typically, if results should be in an Excel sheet, you want to see a formula if you click on each cell. A naive method is using some Excel driver (like XlsxWriter) directly. But if you are dealing with a big Excel sheet (or multiple sheets in one file), this approach becomes quite inconvenient. Therefore, this article presents a library called Portable Spreadsheet - it can easily export defined formulas in Python to many formats, including Excel and JSON.