When working with CSV files exported from Eventbrite, HubSpot, or other platforms, a common request is to make the header row — such as First Name, Last Name, Email, Ticket Type — appear in bold when opened in Excel. This seems simple, but there’s an important technical detail to understand.
Why CSV Can’t Store Bold Formatting
A CSV file (Comma Separated Values) is a plain-text format. It only stores data, not styles. That means instructions like bold, italic, font size, or background colors cannot be embedded inside a CSV. When you open a CSV in Excel, Excel simply displays the text, but it doesn’t receive any style information from the file itself.
If you save a CSV and reopen it, any formatting you manually added in Excel will be lost because the file format doesn’t support it.
How to Make Headings Bold in Excel
If your workflow requires bold headers, there are a few practical solutions:
- Manual Formatting in Excel
- After opening the CSV, select the first row and press Ctrl + B (Windows) or Cmd + B (Mac) to make it bold.
- Quick, but you’ll need to repeat it every time you open a new CSV.
- Use Excel Templates or Macros
- Create a macro that automatically bolds the first row on file open.
- This is useful if you frequently handle CSV exports.
- Export to XLSX Instead of CSV
- If you want permanent bold headers, generate an Excel (.xlsx) file instead of CSV.
- Using libraries like PhpSpreadsheet in PHP, you can set the header row to bold programmatically.
- Example:
$sheet->getStyle('A1:Z1')->getFont()->setBold(true);-
- When opened in Excel, the headers will always display in bold.
Best Practice for Data Exports
- Use CSV when you want maximum compatibility and lightweight files.
- Use XLSX when you want formatting control, bold headers, formulas, or multiple sheets.