RixSheets opens Excel workbooks the way you expect: pick the .xlsx file and it is on the grid, formulas intact, ready to edit. Saving is just as direct — a native Rust xlsx engine writes the workbook back in genuine Excel-compatible form. This page explains what opens, what the engine preserves and how to move between formats without surprises.
Formats RixSheets opens
- .xlsx — modern Excel workbooks open natively, including multi-sheet files, charts and formatting.
- .xls — legacy Excel 97-2003 workbooks open through a compatibility filter.
- .csv — plain delimited text opens in the grid too; see the CSV guide for delimiter and encoding control.
Open any of them from the Home screen, with Ctrl+O (Cmd+O on Mac) or by double-clicking the file in your file manager. Each workbook gets its own tab, so you can keep the source data and the summary model open side by side.
What loads into the grid
When a workbook opens you get the full picture: every sheet as a tab at the bottom, the formula bar on top, number formats, cell colors, borders, merged cells, frozen panes and charts. Formulas stay live — RixSheets recalculates them as you edit, using the same cell references and function names Excel uses.
The Rust xlsx engine
The spreadsheet format is the most demanding of the three office formats: workbooks grow big, and users feel every millisecond. That is why Rixoffice ships a dedicated Rust xlsx sidecar — a compiled, native engine that parses and writes .xlsx packages instead of relying on a slow interpreted layer:
- Opening a workbook streams sheets into the grid quickly, even with hundreds of thousands of rows.
- Saving writes the package directly, without re-encoding parts it does not need to touch.
- The engine runs as a separate process, so a heavy recalculation never freezes the interface.
For you this means two things: speed, and files that stay valid. A workbook saved by Rixoffice opens in Excel, LibreOffice and Google Sheets like any other .xlsx.
What survives a round-trip
| Part of the workbook | What happens when you save |
|---|---|
| Formulas | Kept live and recalculated; references and names preserved |
| Number formats and styles | Written back per cell, exactly as set |
| Multiple sheets | All sheets and their order preserved |
| Charts | Preserved as part of the workbook package |
| Merged cells and frozen panes | Kept exactly as they were |
| Untouched sheets | Saved without being rewritten where possible |
Working with large workbooks
Large files are where the native engine earns its keep. Practical habits that keep things fast:
- Keep raw data on its own sheet and build summaries on another — the engine handles this layout efficiently.
- Use filters and frozen headers instead of splitting workbooks into copies.
- If you receive a giant export as CSV, convert once to .xlsx and work from there; see importing CSV and XLSX.
Saving, converting and sharing
- Press Ctrl+S to save in place as .xlsx — the native engine writes the file directly.
- Use File, Save As to keep a dated copy, or to save the current sheet as CSV for another system.
- Use File, Export as PDF to hand over a fixed, print-ready version of a sheet or range.
- Legacy .xls files can be opened and then saved as .xlsx in one pass, which is the easiest way to modernize an old archive.
RixSheets AI works on any open workbook and is unlimited on every plan, so summarizing a sheet or generating formulas costs no credits at all.
What to explore next
- RixSheets getting started covers formulas, pivot tables and charts in depth.
- Importing CSV and XLSX walks through data import options.
- The byte-preserving engine explains how the suite keeps your files clean on every save.