GRIDFORGE — Local Spreadsheet Studio

A local spreadsheet workspace for XLSX and CSV, with formulas, formatting and careful compatibility checks. No account.

Keep the workbook useful. GRIDFORGE is an independent local spreadsheet application for supported XLSX, CSV and editable GRIDFORGE project files. Open a file you choose, work across sheets, edit data and formulas, then export a new file without overwriting the original. A clean, virtualized grid keeps the focus on the workbook. Use cell or formula-bar editing, range selection, undo and redo, internal copy and paste, fill down, find and replace, row and column insertion, sheet renaming, range sorting and view filtering. Format fonts, emphasis, fill, borders, alignment, wrapping and common number formats. Resize rows and columns or freeze the top rows and left columns. The bounded calculation engine supports English A1 formulas, absolute and relative references, cross-sheet references, conditional logic, aggregates, conditional sums/counts, lookup functions, text operations and dates. It detects cycles and displays formula errors rather than silently replacing them with zero. A list of supported functions and compatibility limits is included in the application guide. CSV import previews the delimiter and preserves leading-zero identifiers. Formula-like CSV text is treated as literal text. Export XLSX with supported sheets, formatting, formulas and cached values; export the active sheet as values-only CSV; or keep an editable GRIDFORGE project backup. Browser downloads create new files, not in-place edits to the selected input. Compatibility is explicit. If an XLSX file contains detected features the editor cannot preserve, it opens as a read-only compatibility preview or is rejected. Modified XLSX export is blocked for read-only previews. Download an unchanged copy of the original input while that tab session is open. Unsupported macros, encrypted files, complex charts, pivots, advanced tables, merged cells, external links and many Excel-specific features are outside this release. The app runs locally with no accounts, analytics, ads, remote conversion server or online formula service. Its manifest requests no permissions or host permissions. It reads only the file you choose or drop, not other files on your disk or pages you visit. IndexedDB saving and single-editor Web Locks require browser support; the interface clearly labels an unavailable-storage session as temporary. Limits: up to 12 worksheets, 5,000 rows by 128 columns per sheet, and 50,000 populated or formatted cells per workbook. XLSX input is limited to 20 MB, CSV to 8 MB and project input to 12 MB, with further expanded-archive and parsing safeguards. Cut/move semantics, embedded charts, macros, arbitrary Excel formulas, cloud collaboration and password encryption are not offered. The formula engine has documented semantic differences from Excel; verify important calculations independently. GRIDFORGE is not affiliated with Microsoft and is not a full replacement for every Microsoft Excel workflow.