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HomeXLS vs CSV
.xls
.csv

XLS vs CSV

Compare Microsoft Excel 97-2003 and Comma-Separated Values formats — understand the key differences and when to use each

Format Overview

XLS

Microsoft Excel 97-2003

Microsoft Excel 97-2003 (.xls) is a spreadsheet file format.

.xlsspreadsheet

CSV

Comma-Separated Values

CSV (Comma-Separated Values) is the simplest and most universally compatible tabular data format. Each line represents a row, with values separated by commas (or other delimiters like semicolons or tabs). CSV is plain text, making it human-readable, lightweight, and compatible with virtually every application — from Excel and Google Sheets to databases, programming languages, and data analysis tools. CSV does not support formatting, formulas, multiple sheets, or data types — all values are stored as text. It's the standard format for data import/export, ETL pipelines, database exports, API responses, and machine learning datasets. For large datasets, CSV offers simplicity and efficiency, though formats like Parquet or XLSX provide better features for complex data.

.csvspreadsheet

XLS vs CSV: Feature Comparison

FeatureXLSCSV
Full NameMicrosoft Excel 97-2003Comma-Separated Values
File Extension.xls.csv
Categoryspreadsheetspreadsheet
Free to Convert✓ Yes✓ Yes
Browser Support✓ All Browsers✓ All Browsers
Convert to Each Other✓ Yes✓ Yes

When to Use XLS vs CSV

Use XLS when you need:

  • •Files in Microsoft Excel 97-2003 format for maximum compatibility
  • •Industry-standard spreadsheet format support
  • •Wide software and platform compatibility

Use CSV when you need:

  • •Files in Comma-Separated Values format for specific workflows
  • •Optimized spreadsheet format features
  • •Modern format advantages and smaller file sizes

Convert Between Them

XLS CSVCSV XLS
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Learn More About These Formats

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Frequently Asked Questions

What is the difference between XLS and CSV?
XLS (Microsoft Excel 97-2003) and CSV (Comma-Separated Values) are both spreadsheet file formats. XLS files use the .xls extension while CSV uses .csv. They differ in compression, quality, compatibility, and intended use cases.
Can I convert XLS to CSV for free?
Yes! Convert999 lets you convert XLS to CSV completely free, directly in your browser. No file upload to any server, no registration needed — your files stay private on your device.
Which is better, XLS or CSV?
It depends on your use case. XLS (Microsoft Excel 97-2003) may be better for certain workflows, while CSV (Comma-Separated Values) excels in others. Consider factors like file size, quality, software compatibility, and your specific needs.
Is it safe to convert files on Convert999?
Absolutely. Convert999 processes all files 100% locally in your browser. Your files are never uploaded to any server, ensuring complete privacy and security.

XLS Converter

Convert from XLS

CSV Converter

Convert from CSV

File Tools

Compress, resize, merge

Convert to XLS

All sources → XLS

Convert to CSV

All sources → CSV

Format Statistics

Trends & data 2025

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