# Importing Excel binary workbooks

Open an `.xlsb` file with File → Open, drag it onto GridCraft, or pass it to the CLI.
GridCraft imports worksheet data into a new workbook and shows the conversion limits.

The import reads worksheet names, visibility, numbers, text, booleans, errors and merged
cells. Formula cells become their **last saved results**, not live formulas. Those results
may be out of date if the source application did not recalculate before saving.

Source formatting is omitted: dates, times, percentages and currencies initially display as
their underlying numbers. The workbook's date system is retained. Charts, images, names,
macros and other workbook features are not imported. GridCraft does not write XLSB files.

Save opens Save As and suggests a new `.xlsx` file. The source XLSB file is not used as the
workbook's save destination; requests to save to `.xlsb` return an error.

```sh
gridcraft-cli info source.xlsb
gridcraft-cli convert source.xlsb imported.xlsx
```

CLI import warnings go to stderr, leaving structured output on stdout available for scripts.