Excel vs CSV: What's the Difference and When to Use Each

Excel and CSV both hold tabular data, but they're very different formats — and picking the wrong one causes lost formatting or broken imports. Here's the difference between Excel and CSV, and when to use each.

What CSV is

CSV (Comma-Separated Values) is plain text: one row per line, values separated by commas. It has no formatting, no formulas, no multiple sheets — just data. That simplicity is its superpower: almost every program on earth can read it.

What Excel (.xlsx) is

An .xlsx file is a rich, compressed format that stores formatting, formulas, charts, multiple sheets, data types and more. It's ideal for working with data, but it's Microsoft-centric and heavier than plain text.

When to use each

Use CSV for importing/exporting between systems, feeding scripts and APIs, and long-term archival. Use Excel when you need formulas, formatting, charts, or several sheets in one file. Rule of thumb: CSV to move data, Excel to work on it.

Converting between them

Move freely between the two: Excel to CSV to export data out, and CSV to Excel to bring it into a formatted workbook. Both run in your browser, so nothing is uploaded.

What you lose in each direction

Saving Excel as CSV drops formulas (values are kept), formatting, and all but the first sheet. Converting CSV to Excel doesn't add anything that wasn't there — it just structures the columns. Knowing this prevents nasty surprises before you hit save.