GS-Calc

GS-Calc is a spreadsheet that can be used for various purposes thanks to its scalability - editing/cleaning CSV, text files with millions of rows, splitting/merging files in the XLSX/XLS, text and other file formats, building complex data models with millions of formulas and around 450 built-in functions. GS-Calc features fast binary lookup's with dynamic internal sorting when processing tens of gigabytes of data or more, 4GB+ workbook files, 32 million rows x 16,384 columns, a unique feature of organizing worksheets in a tree form, pivot tables with 32 million rows, up to 64 processor cores during calculations, built-in Monte Carlo Simulations, array/"spilling" formulas for any functions written by users in C/C++ as plain DLL libraries even to replace all built-in functions; Python integration with UDF functions. You can work in up to 100 synchronized panes for each open workbook to monitor results in various sheets and their regions. GS-Calc can be installed on any portable storage device and used without performing any registry modifications.