About CSV Files
CSV (Comma-Separated Values)
CSV is a simple text-based format for tabular data where values are separated by commas. It is the universal interchange format for data between spreadsheet applications, databases, and programming languages.
Family
Spreadsheets & Data
Extension
.csv
MIME Type
text/csv
Can Use As
HOW CSV
CAME TO BE.
CSV — Comma-Separated Values — is less a format and more a decades-old convention. The first CSV-like files appeared in IBM Fortran in 1972 as "list-directed input", and the format gradually settled into the familiar grid-as-text structure through the 1980s and 90s. It was finally formalized by RFC 4180 in 2005 — over three decades after first appearing in the wild.
That informal history is CSV's blessing and curse. Every spreadsheet, database, statistical package, and programming language on Earth reads and writes CSV. But they all do it slightly differently: quoting rules, line endings, escape characters, and Unicode handling vary wildly, and "it's just CSV" has ruined countless data-import days.
CURIOSITIES &
TRIVIA.
RFC 4180 is a suggestion, not a standard — most CSV files violate it somewhere.
Microsoft Excel saves CSV using the regional list separator (comma in EN, semicolon in DE/FR) — confusing international exchange.
The largest public CSV is probably the OpenStreetMap planet dump at over 100 GB.
A CSV file with commas inside quoted strings handled naively will break hundreds of parsers.
CSV has no native encoding declaration — whether it's UTF-8 or Latin-1 is guesswork.
STRENGTHS &
LIMITATIONS.
Strengths
- Universally readable — every spreadsheet, database, and programming language.
- Human-readable in any text editor.
- Stream-friendly — can process terabytes with constant memory.
- Git-friendly — clean diffs of row changes.
- Tiny overhead vs columnar data structures for simple data.
Limitations
- No standard — quoting, escaping, encoding, and separators vary wildly.
- No type information: 0042 might be an integer, a string, or an error.
- Leading zeros and large numbers often get mangled by Excel auto-conversion.
- Not suitable for hierarchical or binary data.
- Breaks when content contains the delimiter and the parser is naive.
Typical Sizes & Weights
Contact export (1000 rows)
100–300 KB
Analytics export (100k rows)
10–100 MB
Large dataset (1M rows)
100 MB – 1 GB
Full database dump
1 GB – 100 GB
Technical Specifications
- MIME type
- text/csv
- Specification
- RFC 4180 (informational)
- Typical separator
- Comma (;), semicolon, tab, pipe
- Typical encoding
- UTF-8, Windows-1252, ISO-8859-1
- Line endings
- LF (Unix), CRLF (Windows)
CONVERT FROM
CSV
Common Use Cases
Data import/export, database migration, analytics data, bulk uploads.
Popular CSV conversions
The most-requested destinations when starting from CSV.
Frequently Asked Questions about CSV
Frequently Asked Questions
CSV (Comma-Separated Values) is a plain text format for tabular data where each line represents a row and commas separate column values. It is the universal interchange format for databases, spreadsheets, and data analysis tools.
CSV files open in Microsoft Excel, Google Sheets, LibreOffice Calc, Apple Numbers, and any text editor like Notepad or VS Code. Programming languages like Python and R have built-in CSV parsing libraries.
Use CSV for data interchange between systems, database imports/exports, and programmatic processing. Use XLSX when you need formatting, formulas, charts, or multiple sheets that CSV cannot represent.