CSV

in English: comma-separated values (CSV)

basicwidespread

A CSV is a simple text file that stores a table: each row is a record, and the values of the columns are separated by a comma or a semicolon.

In plain terms

Imagine a table written in a grid notebook where you have erased the lines and placed commas between the cells. This is CSV: a table in the simplest possible form, as plain text. It contains no color, font, formula, or chart, only the data itself.

It is so popular because almost every program understands it. Excel, Google Sheets, accounting software, the online store, and Notepad all open it. If two systems cannot agree on anything else, they usually can with CSV.

Compared to an Excel workbook, a CSV is like a bare shopping list next to a colorful, illustrated flyer. It knows less, but anyone can read it, even with a simple text editor.

AI tools also like working with it: a summary, chart, or analysis is quickly prepared from a CSV file uploaded to a chatbot or AI agent because it is a simple table of rows and columns that is easy to process.

How it works

Each line of the file represents a row in the table, such as a customer, an order, or a bank transaction.
Within a row, column values are separated by a delimiter. This is originally a comma, but on computers with Hungarian regional settings, Excel typically uses a semicolon because the comma serves as the decimal separator in Hungary.
The first row is usually a header, containing the column names, for example: name;city;amount.
If a value itself contains a delimiter, quotation mark, or line break, the value is enclosed in quotation marks (with internal quotation marks doubled) to prevent the program from splitting it.
Upon opening, the program splits rows along delimiters and attempts to determine what is a number, what is a date, and what is text.

An everyday example

You download last year's transaction history from your online bank, and among the formats is CSV. You can open it in Excel or upload it to an AI assistant with the request to categorize your expenses and show where most of the money went.

Who is affected

employeeData movement between office systems, such as exporting and importing, most often occurs via CSV files. → Work & HR

entrepreneur, executiveAn online store's product list, an invoicing program's report, and a newsletter contact list can typically be transferred from one service to another in CSV format.

developerWhen loading data, testing, or handling small AI training datasets, CSV is one of the simplest common formats that a coding agent can easily read and write; for large datasets, however, more efficient formats (such as Parquet) are often used. → Code

bank customer, investorBanks and brokerage firms usually make account history and transaction lists downloadable in CSV format. → Money

A common misconception

MythA CSV is the same as an Excel file, just with a different extension.

In realityCSV stores only raw data in a single table: it contains no formulas, formatting, multiple sheets, or charts. If you save an Excel workbook as CSV, all of these are lost.

Limits and risks

There is no single standard that everyone follows: the delimiter can be a comma, semicolon or tab, so it sometimes happens that all the data lands in a single column when the file is opened.
Hungarian accented letters, especially ő and ű, can become unreadable symbols if you open the file with a different character encoding than the one used to save it.
A spreadsheet can arbitrarily transform values: it may strip leading zeros from a phone number or postal code, and interpret a product code as a date.
The file is not encrypted and has no password protection, so do not carelessly send or upload a CSV containing personal data to an AI service.

Similar, but not the same

Excel workbook (XLSX) – XLSX stores formatting, formulas, multiple worksheets, and charts, while CSV stores only the raw data of a single table.
JSON – JSON can describe nested, complex data structures, while CSV only describes flat tables made of rows and columns.
database – A database is a searchable system linking multiple tables and used by many simultaneously, whereas CSV is merely a simple text file.

Related concepts

Broader

File format, structured data, adatcsere

Narrower

–

On the edge

TSV, JSON, XML, spreadsheet, database, training data

A brief history

Comma-separated data entry dates back to the early mainframe era: one of IBM's Fortran compilers already supported it in 1972, long before personal computers became widespread. The format was long regulated only by convention; its best-known common description, the document numbered RFC 4180, was published in 2005, but this too is only a recommendation, not a mandatory standard.

Where things stand

At the end of 2026, CSV remains the most common exchange format for tabular data, handled by virtually all office and business software. AI assistants and agents can also analyze and generate CSV files directly, which further strengthens its role.

Status: 2026 November

Also known as

CSV · CSV file · .csv · comma-separated values · comma-separated values · Comma-separated values · semicolon-delimited file · CSV-export

Sources

This entry was machine-edited and has undergone machine expert review; the “In the news” section updates automatically from Agent Age stories.