What Is a CSV File?

Learn how to open, edit, and convert CSV files

Screenshot of several CSV files in Windows 10 that open with OpenOffice Calc
CSV Files.

A CSV file is a Comma Separated Values file. All CSV files are plain text files, can contain numbers and letters only, and structure the data contained within them in a tabular, or table, form.

Files ending in the CSV file extension are generally used to exchange data, usually when there's a large amount, between different applications. Database programs, analytical software, and other applications that store massive amounts of information (like contacts and customer data), usually support the CSV format.

A Comma Separated Values file might sometimes be referred to as a Character Separated Values or Comma Delimited file, but regardless of how someone says it, they're talking about the same CSV format.

CSV is also an acronym for comma separated variable, circuit switched voice, and colon separated value.

How to Open a CSV File

Spreadsheet software is generally used to open and edit CSV files, such as the free OpenOffice Calc or Kingsoft Spreadsheets. Spreadsheet tools are great for CSV files because the data contained in the file is usually going to be filtered or manipulated in some way.

To view and/or edit your CSV file online, you can use Google Sheets. To do that, upload your file to Google Drive via New > File upload, right-click the file in Google Drive when it's done uploading, and choose Open with > Google Sheets.

You can also use a text editor to open CSV files, but large ones will be very difficult to work with in these types of programs. If you want to do this, see our favorites in this Best Free Text Editors list.

Microsoft Excel supports CSV files, too, but the program isn't free to use. Even so, it's probably the most commonly used program for CSV files.

Considering the number of programs out there that support structured, text-based data like CSV, you may have more than one program installed that can open these types of files. If so, and the one that opens by default when you double-tap or double-click on CSV files in Windows isn't the one you like to use with them, please know that changing that program is very easy.

See How to Change File Associations in Windows for a tutorial. Any program that supports CSV files is fair game for this "default" program choice.

How to Convert a CSV File

Since CSV files store information in a text-only form, support for saving the file to another format is included in lots of different online services and downloadable programs.

All of the desktop programs mentioned above can convert a CSV file to Microsoft Excel formats like XLSX and XLS, as well as to TXT, XML, SQL, HTML, ODS, and other formats. This conversion process is usually done through the File > Save as menu.

You can also use Google Sheets to save the CSV file to another format. From the File > Download as menu, pick XLSX, ODS, PDF, or any other supported format.

There are also some free file converters that run in your web browser, like Zamzar for instance, that can convert CSV files to some of the formats listed above but also to PDF and RTF.

The CSVJSON tool (guess...) converts CSV data to JSON, super helpful if you're importing massive amounts of information from a traditional application into a web-based project.

You cannot usually change a file extension (like the CSV file extension) to one that your computer recognizes and expect the newly renamed file to be usable. An actual file format conversion using one of the methods described above must take place in most cases. However, since CSV files can only contain text, you can rename any CSV file to any other text format and it should open, albeit in a less helpful way than if you had just left it at CSV.

Important Information on Editing CSV Files

You'll probably only encounter a CSV file when exporting information from one program to a file, and then use that same file to import the data into a different program, especially when dealing with table-oriented applications.

However, you may at times find yourself editing a CSV file, or making one from scratch, in which case the following should be kept in mind:

A common program used to open and edit CSV files is Microsoft Excel. Something important to understand about using Excel, or any other similar spreadsheet software, is that even though those programs appear to provide support for multiple sheets when you're editing a CSV file, the CSV format does not support "sheets" or "tabs," so data you create in these additional areas won't be written back to the CSV when you save.

For example, let's say you modify data in the first sheet of a document and then save the file to CSV — that data in the first sheet is what will be saved. However, if you switch over to a different sheet and add data there, and then save the file again, it's the information in that recently-edited sheet that will be saved — the data in the first sheet will no longer be accessible after you've shut down the spreadsheet program.

It's really the nature of the spreadsheet software that makes this mishap confusing. Most spreadsheet tools support things like charts, formulas, row styling, images, and other things that simply can't be saved under the CSV format.

There's no problem so long as you understand this limitation. This is why other, more advanced table formats exist, like XLSX. In other words, if you want to save any work beyond very basic data changes to a CSV, don't use CSV anymore — save or export to a more advanced format instead.

How CSV Files Are Structured

It's easy to make your own CSV file. Just get your data sorted how you want in one of the tools mentioned above, and then save what you have to the CSV format.

However, you can also create one manually, yes — from scratch, using any text editor.

Here's one example:

Name,Address,Number
John Doe,10th Street,555

All CSV files follow the same overall format: each column is separated by a delimiter (like a comma), and each new line indicates a new row. Some programs that export data to a CSV file may use a different character to separate the values, like a tab, semicolon, or space.

What you see in the example above is how the data would appear if the CSV file were opened in a text editor. However, since spreadsheet software programs like Excel and OpenOffice Calc can open CSV files, and those programs contain cells to display information, the Name value would be positioned in the first cell with the John Doe in a new row just below it, and the others following the same pattern.

If you're embedding commas or using quotation marks in your CSV file, read edoceo's and CSVReader.com's articles for how you should go about that.

Still Having Problems Opening or Using a CSV File?

CSV files are deceptively simple. As straightforward as they are at first look, the slightest misplacement of a comma, or a basic confusion like the one we discussed above, can make them feel like rocket science.

If you run in to trouble with one, see my Get More Help page for information about contacting me on social networks or via email, posting on tech support forums, and more. Let me know what's going on with the CSV file you're working with, or trying to work with, and I'll do my best to help.

However, also keep in mind that you might not be able to open the CSV file or read the text within it, for the simple reason that you're confusing another file for one in the CSV format. Some files share some of the same file extension letters as CSV files but aren't actually in the same format, or even a remotely similar one.

CVS, CVX, CV, and CVC are just a few examples where the files probably can't open in a spreadsheet program even though the suffix looks a lot like CSV. If this is the case with your file, research the real file extension on Google or here on Lifewire, to see its compatible openers or converters.