To keep decimal values readable when you share a spreadsheet across regions, set the file’s number conventions deliberately and check how the recipient’s app handles them. On a Mac, Apple Numbers can store language and region settings in a spreadsheet; Excel for Mac offers separator preferences; Google Sheets uses a spreadsheet-wide locale. A displayed comma or period can change without changing the underlying numeric value, but plain-text exports need extra care.

First decide what “keep the separator” means

There are two different goals: preserve numeric values so they calculate correctly, or preserve the exact punctuation people see. Spreadsheet apps can store a number such as one and a half as a numeric value, then render it as 1.5 or 1,5 according to formatting rules. In Excel, number formatting affects appearance rather than the stored value used in calculations. Microsoft explains number formats in Excel.

If the exact visible mark matters, the recipient’s software and the file format matter too. A workbook may retain spreadsheet formatting, while CSV is plain text: its delimiter and decimal mark can be interpreted differently by different apps. For files that must remain calculable, share the native workbook format where possible, and agree on the region or locale the file should use.

In Numbers for Mac, set the spreadsheet’s region

Numbers has a per-spreadsheet language and region setting that controls conventions such as decimal points, thousands separators, currencies, and dates. To set it, open the spreadsheet and choose File > Advanced > Language & Region, then select the language and region and click OK. Apple says the punctuation in numbers changes with this setting, including for existing table and chart data. The change applies to that spreadsheet rather than requiring you to change the Mac’s general region. Apple’s Numbers guide explains the setting and its effects.

For a new file, Numbers also lets you choose a language when creating a spreadsheet: hold Option while choosing File > New, then use the Language menu in the template chooser. Choose the intended region before entering or importing data, especially when collaborators expect different date and decimal conventions. Apple notes that you can’t change this setting for a shared spreadsheet, so decide before sharing; if the control is unavailable after collaboration begins, coordinate on a copy or new file with the desired settings.

In Excel for Mac, choose whether to follow system separators

Excel for Mac documents an Use system separators preference. In Excel, open Excel > Preferences, find the advanced or editing options, and either leave Use system separators selected or clear it and enter the decimal and thousands separators you need. Microsoft’s current guidance documents these controls for Excel for Mac, though preference labels or locations can vary by version. See Microsoft’s Excel advanced options.

This changes Excel’s separator behavior on that Mac; it does not establish a universal setting for every recipient’s copy. If you choose custom separators, verify both decimal and thousands marks, then reopen the file or test a copy on a system using the destination locale. A custom cell number format can control display, but it should not be confused with changing the stored value. Microsoft distinguishes number appearance from the underlying value.

Check the receiving app before sending CSV

CSV has no workbook-level locale setting that reliably tells every spreadsheet app how to interpret decimals. If your data uses a comma decimal mark, a comma-delimited CSV can be ambiguous; the recipient may split a value across columns or interpret it as text. Agree whether the file uses comma or period decimals and which character separates columns. When the recipient’s software supports an import dialog, have them select the delimiter and verify the preview before importing.

For shared Google Sheets, locale belongs to the spreadsheet. A change to File > Settings > General > Locale changes default number, date, and currency formatting for the entire spreadsheet, and everyone working in it sees the change. That makes the locale a collaboration decision rather than a personal display preference. Google documents the spreadsheet-wide locale behavior.

Use a short handoff check

Before sending the file, keep a small test value such as 1234.56 or 1234,56 in a copy and confirm the intended rendering, thousands mark, date interpretation, and calculations. Ask the recipient to verify the same values in their app. If the numbers will go through CSV, agree on delimiter and decimal mark first, and test import with a few representative rows. If recipients need different visual conventions, preserve one agreed numeric source and create separate formatted copies or exports rather than repeatedly changing the shared original.

The practical rule is to set a spreadsheet-specific locale when the app supports it, use system settings only when that is the desired Mac-wide behavior, and treat CSV as a text interchange that needs an explicit format agreement. That keeps the file’s meaning and the recipient’s expectations aligned without assuming that a comma or period will travel unchanged between apps.

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