what are file formats?

File formats are the way information (data) is written (or stored) on your computer.

We already know that all our documents, photos, videos etc are just files to a computer. A computer doesn't "see" that picture of your first child, it only "sees" a file.

Now in order for the machine to store these files, they have to be written onto the computer.

You can think of file formats as being like human language. If I spoke French or German, I could have written this in French or German.

It would be the same information, just written in a different language, or a different format.

Home » Free Computer Course. » What are File Formats

understanding file formats.

When you save a file, a picture, a document etc, to your computer, it's saved in a format.

The format is set by whichever program you've used to create the file. All programs have what's called a default format.

But I'm getting ahead of myself. we first need to know a little more about what file formats are.

So here goes.......

Let's say I need to get these supplies from the shops.

I'll make a list, a shopping list.

But what language do I use?

What language do I write the list in? What format do I use?

English, French or German? Or whatever.

bread, milk & butter.

Well since I only speak one language (or format), I have no choice, I have to write it in English.

I have to use the English language (the English format). Because that's all I know.

Who knows what I'll come back with if I try to write it in French or German?

in german.

Many of you out there are way smarter than me, and will have 2 languages or more.

You may well speak English & French, or French & German, all 3 languages or more.

So you would have a choice of which language (or format) you used.

in french.
in german.
computer file formats.

That's exactly how File Formats work on a computer.

Every file (picture, document, video or music track) has been created by a program. Just like I created the shopping list.

And that program created the file in a particular format, or a particular language.

And just like human languages, there are thousands of file formats.

languages and file formats.


file formats in action.

Unlike human languages, we can't actually see a file's format. We can't usually see how it's been written down.

But we can see, or experience, the effects of a file's format. We can see what happens when we mix formats around.

Try doing this on your machine.

We're going to create a simple document in a program called Wordpad. It'll be saved in Wordpad's default format (which is called RTF).

Then we'll try to open that document in Notepad. Let's see what happens?

Open Wordpad & then resize the window so that it's in the top half of your screen.

Then open Notepad & resize it to take up the bottom half of the screen.

If you're not sure how to size/move a program window like this, you've probably missed this guide, Resizing a Program Window.

wordpad on top & notepad beneath.

Your screen should look something like the image above. Don't worry about getting it exactly the same. We just want Wordpad visible on top and Notepad visible underneath.

In Wordpad type -

Can you read this?

Then save the file onto your Desktop with the file name "Wordpad Doc".

type "can you read this".

You should be pretty good at saving files by this stage of the course, but just in case you missed it How to Save a File on a PC

So what we've saved is just a single line of text, nothing special about it.

Notepad should be able to read it, right? It should be able to open it.

Well, let's try it.

In Notepad, try to open the file "Wordpad Doc".

Can you find it? Have you double-checked you're looking in the Desktop folder? We saved it onto the Desktop.

Well, I couldn't find it either.

The reason we can't see the file Wordpad Doc is that it's been saved in a file format (or language) that Notepad doesn't understand.

just where is "Wordpad Doc"?

Notepad is quite simply ignoring any files written (saved) in formats that it doesn't understand.

So when we're trying to open Wordpad Doc, it seems as if it doesn't exist.

Lots of programs will do this. Not just Notepad. If they don't speak the lingo, they simply ignore it.

If they can't read the format, they won't show the file.

show all file formats.

As I said above, most programs will simply ignore file formats that they don't understand.

But all is not lost. We can make Notepad at least try to open our Wordpad Doc file.

At the bottom of the screen, click the small arrowhead in the file type box.

Then click ALL FILES.

This tells Notepad to show every file type (format). Even the ones it can't read (understand).

click ALL FILES.

Most programs have this option (show all files) when you're trying to open a file.

After clicking ALL FILES, you'll see every file that you've got on your Desktop.

Scroll through them and find "Wordpad Doc".

Once you've found it, left-click once to select it, then click the OPEN button.

Well, that's weird.

well, can you read this?

Notepad is quite a determined little program, and although it doesn't really understand the file Wordpad Doc, it's had a go at it.

Rather like us, trying to decipher something written in a foreign language.

It happens because Wordpad is a much bigger program than Notepad.

Wordpad can create (save) files in different formats (or languages).

Wordpad's default format is called RTF (Rich Text Format).

Poor old Notepad, though, can only read files saved in the TXT (text) format.

Again, you can think of these formats as being languages. So you could think of Notepad as only having 1 language, while Wordpad is multilingual.


What we're trying to do here, is to demonstrate how file formats work or don't.

Do try it out for yourself, I know it sounds a little complicated, but you can do everything here.

file formats.

changing file formats.

So Notepad had a go at reading the file but made a bit of a mess of it.

That's similar to handing me a note written in French, German or any language other than English.

But what if we could translate the note?

What if we could get Wordpad to save the file in a format (in a language) that Notepad understands?

Can it be done, and how do you do it? Will it work?

As I said earlier, Wordpad is multilingual. By that, I mean it can create (or save) documents in different file formats (or different languages).

So let's help Notepad out. We'll re-save the file in Wordpad, but this time, we'll change the format that Wordpad uses to save the file.

In Wordpad, left-click FILE, then click SAVE AS.

On the menu, left-click PLAIN TEXT DOCUMENT.

Change the file name to be "Wordpad doc 1" and save it to your Desktop.


When you click the SAVE button, you'll probably get this warning box open.

We'll come back to why this happens later, but for now, click the YES button.

click YES.

Now go back to Notepad and try to open the file "Wordpad doc 1".

WOW, we can see it without having to change the file type to ALL FILES.

Go ahead & open it.

open it.

Now Notepad can read the document.

It can do so because we told Wordpad to save the file in a format that Notepad can understand.

So even though the actual message "Can you read this?" is exactly the same, it depends on which format (or language) it's saved in.

Rather like our shopping list earlier.

hoorah, notepad can do it.

Notepad can only read or write in the Text File Format (txt).

So any file that isn't written in this format is gobbledegook to Notepad.

Wordpad, on the other hand, can read & write in several file formats. Including the Text File Format which Notepad uses.

It's just like people and languages. If I pass you a note written in French, and you understand French, you'll be able to read it.

But if you pass me a note written in German, I don't understand German, so I'll end up trying to guess what it says.


Re-saving the file so that Notepad can open it.

Very easy to do, and more than a little satisfying when the message pops up.

re-saving the file.

which brings us back to the save as window again.

We covered the Save As window here How to Save a File on a PC  and I bet you thought you knew all that could be known about the Save As window. Well, it has one more little secret. One more function that we can use.

In all the previous guides we've been using Notepad to save simple files to play around with.

And Notepad can only save a file in the Text File Format (txt).

But most programs can save files in many different file formats. As we've just seen with Wordpad.

Close Notepad out of the way and then maximise Wordpad.

Click FILE and then click NEW, to start a new document (a new file).

On the blank page, type something, anything will do.

type something new into wordpad.

Now click FILE, and then SAVE. Just as you'd normally do to save the file.

The SAVE AS window opens.

Underneath the FILENAME box, you'll see the SAVE AS TYPE box.

the SAVE AS TYPE box.

We can read, SAVE AS TYPE, to actually mean, "Which file format would you like to save this file in".

Currently, it says "RICH TEXT FORMAT (RTF)".

That's the default file format in Wordpad. The native language for Wordpad to use. And if you don't change it, that's the format that the file will be saved in.

But we can change it. Oh yes we can.

To the far right of the box, you'll see an arrowhead.

Click the arrowhead.

the file formats wordpad can use.

You'll see a list of the file formats that Wordpad can use.

  • Rich Text Format (RTF). Which is Wordpad's default format.
  • Office Open XML Document.
  • OpenDocument Text
  • Text Document. Which is Notepad's format.
  • Unicode Text Document.

Wordpad can save our documents in any of these file formats. It can also open any file written any of these formats.

But here's the thing, just like different people read & write in different languages, so do computer programs.

Remember that Notepad had problems reading the Rich Text Format (RTF).

And this can happen to you because it affects all types of files, not just text files.


why so many formats?

That my friends, would be a very good question.

And it brings us back to that message that Wordpad threw up earlier when we saved the file as a Plain Text Document.

The Plain Text Document format that we were changing to is a very old file format.

It's designed to handle just text.

It has very few options by today's standards.

And so Wordpad is warning you that, if you've done anything fancy in your document, it will be lost if you save it as Plain Text.

warning, you are about to...

Rich Text Format, however, can do more than just save text.

Using  RTF, for instance, you can whack in a picture.

Now that's fancy.

we have pictures.

Different file formats allow us to do different things. Or maybe they simply work better than their predecessors.

Sometimes several developers are working on similar projects at the same time, and so we get rival formats appearing, that seemingly do the same thing. Think about VHS & Betamax.

For us, here on this course, we don't need to know everything about file formats. We simply need to know that they exist. That they are there and how we can use them.

There are many thousands of file formats. Some have been around forever, many have fallen into disuse, while others will come to dominate that file type.

They're being developed constantly, below is just a very small selection of some of the file formats you may come across.

audio/music MP3, MP4, FLAC, WAV, WMA, AAC, CDA, MIDI
compressed files 7Z, RAR, ZIP
documents DOC, DOCX, ODT, PDF, RTF, TXT, WPD
pictures/images TIFF, BMP, JPEG, GIF, PNG


tick blue

i speak your language.

So that's what file formats are, they're just a sort of written language for computers.

Next, we're uninstalling old programs and apps.

at home computer extra guides.

Not part of the course, but you might be interested.

how a PC stores data

How does a computer store all those documents and pictures anyway?

It's all ones and zeros.

how to backup your computer.

How to backup your computer using Windows 10 System Backup.

No program install needed.