How do you batch convert CSV files to XLSX on a Mac?

By Kayabyte · Last updated 31 October 2026

To convert one CSV to XLSX on a Mac, open it in Excel and choose File, Save As, Excel Workbook. For many files there is no batch command in Excel for Mac; free options are LibreOffice in Terminal or a script, and Gridhand converts a whole folder in one run, with encoding and delimiter detection and leading zeros kept.

One file, in Excel

Open the CSV in Excel, or use Data, Get Data, From Text/CSV to choose the file origin (encoding) and delimiter.
Check that accented characters look right and that long numbers and IDs are not shown as 1.23E+15 or lost their leading zeros.
File, Save As, and choose Excel Workbook (.xlsx).

Many files, free

LibreOffice in Terminal. After installing LibreOffice, in the folder with the CSVs: /Applications/LibreOffice.app/Contents/MacOS/soffice --headless --convert-to xlsx --outdir out *.csv. It uses LibreOffice’s own guesses for encoding and delimiter, so check the results.
A script. Python with pandas or openpyxl can loop over a folder, at the cost of writing and maintaining it.
Excel one by one, as above.

What goes wrong

Encoding: a CSV saved as Windows-1252 or UTF-16 shows garbage characters when read as UTF-8.
Delimiter: semicolon-separated files (common in Europe) arrive as one wide column.
Leading zeros and long numbers: 00123 becomes 123, and 16-digit IDs lose precision.
Dates: 03/04/2026 can become March or April depending on your Mac’s region.

With Gridhand

Gridhand Convert reads CSV, TSV and delimited text. It detects the encoding (BOM, UTF-8 validity, UTF-16, Windows-1252 as a fallback) and the delimiter (comma, semicolon, tab or pipe, by consistency over the first rows), handles quoted line breaks and ragged rows, and only turns text into numbers or dates when the whole column agrees, so IDs with leading zeros stay text. You can override the encoding and delimiter, set the decimal mark, choose header options, and put everything into one workbook. Outputs are formatted .xlsx files, written to a folder you choose; originals are never modified.

Steps with Gridhand

Drop the CSV files, or a folder, into Gridhand and choose Convert.
Choose “CSV, TSV or text to XLSX”. Look at the preview; if the text looks wrong or everything is in one column, change the encoding or delimiter.
Choose an output folder and press Run.

Free for up to 3 files per run; Gridhand Pro is USD 49 once. Download Gridhand

Questions

Can it convert a whole folder? Yes. Add the folder, with or without subfolders, and filter by file type or name.

Why does my CSV open in one column? The delimiter is not a comma. Gridhand detects semicolon, tab and pipe, or you can pick one.

Will leading zeros survive? Yes, in Gridhand’s conversion: a column becomes numbers only when every value is a plain number.

Does it need Excel? No.

Microsoft and Excel are trademarks of the Microsoft group of companies. Gridhand is made by Kayabyte and is not affiliated with or endorsed by Microsoft.