DOCX vs DOC: What’s the Difference?
Word files come in two main types: DOC and DOCX. They look the same when you open them. They both hold text, tables and pictures. So what’s the difference, and does it matter which one you use?
It does matter, a little. This guide explains the difference in plain words, shows you a side-by-side table, and tells you which one to choose.
The short answer
DOC is the old Word format, used from Word 97 to Word 2003. DOCX is the new format, used since Word 2007. DOCX files are smaller, safer and easier for other apps to read. Unless you have a special reason, use DOCX.
DOCX vs DOC at a glance
| DOCX | DOC | |
|---|---|---|
| Introduced | 2007 (Word 2007) | 1997 (Word 97) |
| How it’s stored | A ZIP folder of XML files | One binary file |
| File size | Smaller | Larger |
| Open standard | Yes (Office Open XML) | No, but documented by Microsoft later |
| Can hold macros | No (DOCM can) | Yes |
| Recovery if damaged | Easier | Harder |
| Newest Word features | Yes | No |
| Opens in modern apps | Almost all | Most, but not all |
What is a DOC file?
DOC was the main Word format for about ten years. It stores everything in one binary file. “Binary” just means the data is packed in a way that only makes sense to a program, not to a person reading it.
For a long time, only Microsoft really knew how DOC files worked inside. Other apps had to guess. That’s why old Word files sometimes looked wrong in other programs.
You’ll still see DOC files today. They come from old computers, old templates and some business systems that were never updated. If you have one, our guide on how to open a DOC file shows five free ways.
What is a DOCX file?
DOCX arrived with Word 2007. Microsoft built it on an open standard called Office Open XML. Instead of one binary file, a DOCX file is a ZIP folder. Inside are smaller files written in XML, a plain text code that computers and people can both read.
Because the standard is public, apps like Google Docs, LibreOffice and Apple Pages can read DOCX files accurately. You can learn more in our guide on what a DOCX file is.
The five differences that matter
1. File size
DOCX files are compressed, just like a ZIP file. A document with pictures can be much smaller as DOCX than as DOC. Smaller files are quicker to email and take less space.
2. Safety
Macros are small programs that can run inside Word. They’re useful for some office tasks, but they can also be used by harmful files. DOC files can hold macros. Normal DOCX files can’t. If a Word file needs macros, it has to be saved as DOCM, which makes it easy to spot.
That means a plain DOCX file is a safer format to receive from people you don’t know well.
3. Recovery
If a file gets damaged, a DOCX file is easier to rescue. Since it’s made of separate parts, a broken picture doesn’t always break the whole document. Tools can often pull the text out even when Word says the file is damaged. Read more in our guide to DOCX files that won’t open.
4. Compatibility with other apps
DOCX opens in almost every modern word app, online viewer and phone app. DOC opens in most of them, but not all. Some newer tools, including our own online DOCX viewer, only read DOCX.
5. New features
Word features added after 2007 only work fully in DOCX. If you save a modern document as DOC, Word may warn you that some features will be lost or changed.
When should you use DOC?
Almost never. The only good reasons are:
- Someone still uses Word 2003 or older and can’t open DOCX files.
- A company system or form only accepts DOC files.
- You’re working with a very old template that breaks when converted.
Even in these cases, check first. Most “we need DOC” rules are old and nobody has updated them.
When should you use DOCX?
Pretty much always. Use DOCX when you:
- Send a CV or cover letter
- Share a document someone else will edit
- Save school or work documents
- Want the smallest, safest Word file
And if the other person only needs to read or print your document, consider a PDF instead. Our guide on converting DOCX to PDF shows how.
How to convert DOC to DOCX
Converting takes about a minute. Here are the quickest free ways:
- Microsoft Word: open the DOC file, choose File, then Save As, and pick Word Document (*.docx). Newer versions also show a Convert button under File, then Info.
- Google Docs: upload the DOC file to Google Drive, open it with Google Docs, then choose File, Download, Microsoft Word (.docx).
- LibreOffice Writer: open the file, choose File, Save As, and pick Word 2007-365 (.docx).
For every step with pictures of each menu, read our full guide on how to convert DOC to DOCX for free.
How to convert DOCX to DOC
If you really need the old format, you can go the other way.
- Word: choose File, Save As, and pick Word 97-2003 Document (*.doc). Word will run a check and tell you if anything will change.
- LibreOffice: choose File, Save As, and pick Word 97-2003 (.doc).
Keep your DOCX file too. That way you don’t lose any newer features.
How to tell which one you have
Look at the end of the file name. If it ends in .doc, it’s the old format. If it ends in .docx, it’s the new one.
If you can’t see the ending on Windows, open File Explorer, click View, then Show, and tick File name extensions. On a Mac, select the file and choose File, then Get Info.
When a file opens in Word, the title bar may also say Compatibility Mode. That’s Word’s way of telling you the file is in an older format.
What is Compatibility Mode in Word?
When you open a DOC file in a newer version of Word, it shows [Compatibility Mode] next to the file name. This means Word is limiting itself to features the old format can handle.
To leave Compatibility Mode, go to File, then Info, and click Convert. Word will turn the file into DOCX. Then save it.
Other Word formats you might see
| Extension | What it is |
|---|---|
| .docm | A DOCX file that can hold macros |
| .dotx | A Word template |
| .dotm | A Word template that can hold macros |
| .dot | An old Word template |
| .rtf | Rich Text Format, a simple format most apps read |
| .odt | OpenDocument Text, used by LibreOffice |
Which format should I use for a CV?
Use DOCX or PDF, never DOC. Most job sites and hiring systems accept DOCX, and many recruiters prefer it because they can add notes or copy details easily. A PDF is better when you want your layout locked exactly as you made it.
If a job ad asks for a “Word document”, send DOCX. If it doesn’t say, a PDF is usually safe. Before sending, open your CV in a free viewer to check it looks right on a device without Word. Our online DOCX viewer is handy for this.
Which format do schools and offices want?
Almost all schools, universities and offices use DOCX today. Their systems are built around Microsoft 365 or Google Workspace, and both handle DOCX perfectly.
If your school’s upload page rejects your file, check the file name first. It should end in exactly .docx. Odd names like essay.docx(1) can cause uploads to fail. Our guide on fixing strange DOCX file names explains the fix.
Can every device open both formats?
Most can, but DOCX has the edge. Here’s a quick look:
- Windows and Mac with Word: both formats open fine.
- Google Docs: opens both.
- iPhone and iPad: the Files app previews both, and Pages opens both.
- Android: Google Docs and the Word app open both.
- Online viewers: almost all read DOCX, but many skip DOC.
So if you want the widest reach, send DOCX.
Frequently asked questions
Is DOCX better than DOC?
Yes, for almost everyone. It’s smaller, safer and works with more apps.
Can I open a DOCX file in Word 2003?
Not on its own. Microsoft once offered a free Compatibility Pack for older Word versions, but it’s no longer supported. The easier fix is to open the file with a free modern tool like our DOCX viewer or Google Docs.
Can I rename a DOC file to DOCX?
No. Renaming doesn’t change what’s inside. The file will fail to open. You need to convert it using Save As or a free tool.
Do I lose formatting when converting DOC to DOCX?
Rarely. Text, tables and pictures come across fine. Very old layouts may shift a little, so check the new file before you delete the old one.
Why does my DOC file open in Compatibility Mode?
Because it’s in the older format. Use File, Info, Convert to update it.