CSV is a plain text file where each line is a row and each comma is a column — the simplest way to move structured data between applications. There are two types of people: those who know what a CSV is, and those who've been opening them in Notepad and wondering why the columns don't line up. No formatting, no formulas, no data types, no colours, no merged cells. Just raw data. That simplicity is exactly why CSV has survived for decades while proprietary formats come and go. Every database can export CSV. Every spreadsheet can import it. Every programming language can parse it in about three lines of code. The catch is that there's no real standard — different tools handle quoting, encoding, and delimiters differently, which is why importing a CSV sometimes turns your dates into numbers and your names into mojibake.
Technical details
Full Name
Comma-Separated Values
MIME Type
text/csv
Developer
N/A (open format)
Magic Bytes
N/A
Safety
.csv is a known, safe format.
What opens it
Any text editor
FREEAll
Microsoft Excel
SubscriptionAll
Google Sheets
FREEWeb
LibreOffice Calc
FREEAll
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FAQ
Why does my CSV look wrong in Excel?
Excel sometimes misinterprets delimiters or character encoding. Try using File → Open instead of double-clicking, and select UTF-8 encoding and comma delimiter.
What's the difference between CSV and Excel (XLSX)?
CSV is plain text — just data, no formatting. XLSX is a full spreadsheet format with formulas, formatting, charts, multiple sheets, and data types. CSV is for exchanging raw data between systems. XLSX is for working with data in a spreadsheet. Use <a href="https://fwip.app/tools/csv-to-xlsx/">fwip</a> to convert between them.
How do I open a CSV file properly?
Don't double-click it — that opens it in Excel with default settings that often mangle the data. Instead, open Excel first, use File → Open (or Data → From Text/CSV), and choose UTF-8 encoding with comma as the delimiter. Google Sheets and LibreOffice Calc also handle CSV import well.
Why are special characters broken in my CSV?
Character encoding. Most modern CSVs use UTF-8, but some older tools export in Latin-1 or Windows-1252. When the importing application guesses the wrong encoding, accented characters and symbols turn into garbled text. The fix is to specify UTF-8 encoding when importing.