CSV vs XLSX: Which Spreadsheet Format Should You Use?

Both CSV and XLSX are everywhere in data work, but they serve different purposes. Choosing the wrong format can lead to data corruption, compatibility issues, or unnecessary complexity. Here’s when to use each.

CSV (Comma-Separated Values)

CSV is the universal format. Every programming language, database, and spreadsheet application can read it.

Pros:

• Universal compatibility — works everywhere
• Human-readable in any text editor
• Small file sizes
• No vendor lock-in
• Easy to version control with Git

Cons:

• No formatting (no bold, colors, or cell styles)
• No multiple sheets
• No formulas
• Encoding issues with special characters
• No data type information (everything is text)

XLSX (Excel Open XML)

XLSX is Microsoft Excel’s modern format. It supports rich formatting, formulas, multiple sheets, and data types.

Pros:

• Multiple sheets in one file
• Formulas and calculated fields
• Cell formatting, charts, and styles
• Data type preservation (dates, numbers, currency)
• Widely used in business

Cons:

• Larger file sizes (XML-based, even when compressed)
• Requires specific software to read properly
• Hard to diff or version control
• Can contain macros (security risk with .xlsm)
• Formatting can break across Excel versions

When to Use CSV

• Importing/exporting data between systems
• Sharing raw data for analysis
• Database imports and exports
• Data pipelines and ETL processes
• Publishing open data
• Version-controlled datasets

When to Use XLSX

• Reports that need formatting and presentation
• Multi-sheet workbooks with related data
• Financial models with formulas
• Sharing data with non-technical stakeholders who expect Excel
• Data that needs charts embedded in the file

The Best of Both Worlds

With TablePage, you can upload either format and get the same result: a clean, interactive dataset page with charts and insights. Your audience doesn’t need to care about the original format — they just see explorable data.