On a Mac, with a spreadsheet, and a PDF deadline. Excel for Mac can do it, Numbers can do it, and a browser can do it. The right one depends on the file and your setup.
Excel for Mac's native export
File > Save As > PDF. Same options as Windows Excel. Best quality, fastest if Excel is already open. Embeds fonts, preserves layout, handles charts as images.
For people who use Excel daily, this is the default. No advantage to looking elsewhere.
Numbers as an alternative
Open the XLSX in Numbers (File > Open). Numbers imports XLSX reasonably well, though complex spreadsheets may simplify. Then File > Export To > PDF.
Use Numbers if you don't have Excel installed. Watch for formula compatibility — some Excel functions don't have Numbers equivalents and may show errors after import.
The browser route
Flint's Excel to PDF in Safari handles both XLS and XLSX. No app needed, no compatibility worries.
Good for one-offs when you don't have Office and don't want to wrestle with Numbers' XLSX import. Conversion runs server-side, so it works the same on a 2017 MacBook as on a current M-series.
macOS Print > Save as PDF
From any app: Cmd+P, then PDF dropdown > Save as PDF. Works from Excel, Numbers, even Quick Look. The PDF reflects whatever the app would have printed.
Useful as a fallback when the dedicated PDF export options aren't available.
FAQ
Numbers or Excel for the best PDF?
Excel for Mac if you have it. Numbers if you don't. Quality is similar for standard spreadsheets.
Will charts come across in Numbers?
Yes, though Numbers may render them slightly differently from Excel. Check the result before sending.
Does Apple Silicon affect this?
No — all methods work on M-series Macs without compatibility issues.
Can I batch convert?
macOS Automator supports batch Excel-to-PDF if Excel is installed. For online, one file at a time on the free flow.
Three roads, same destination. Convert your Excel to PDF in the way that fits.