# AZW vs. AZW3



## DYB (Aug 8, 2009)

So I'm a bit confused by these different formats.  I'm confused because I always download books to my computer and then transfer to my Kindle.  I actually have a couple of Kindles, one of which is used by my father.  There have been multiple titles that I downloaded for my Kindle and it was an AZW3 format, but the one downloaded for the Kindle my father uses was AZW.  Why is that?  It's the same Kindle model (the current $69 one), so why the difference in the download format?


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## Leslie (Apr 7, 2008)

AZW3 is the format for Kindle Format 8 which has enhanced features. I think it won't affect you as far as reading goes--it is more of an issue for publishers (both large and small) and how they format their books.

L


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## SusanCassidy (Nov 9, 2008)

Maybe the one used by your father doesn't have an update that yours does?


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## DYB (Aug 8, 2009)

Is AZW3 the newer format then?  It's possible my father's Kindle isn't up to date in its software!


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## Ann in Arlington (Oct 27, 2008)

DYB said:


> Is AZW3 the newer format then? It's possible my father's Kindle isn't up to date in its software!


It probably wouldn't hurt to check to see if he has all the updates. . .they're easily found via Kindle Support. If he doesn't usually have wireless on, and didn't do it manually himself, he might not.

If it's one of the ones that was $79 originally, there was a software update for that model. The version number should be 4.1.0.

If it is the latest $69 model, and was purchased since that pricing change, it came with that version already.

I'm unclear whether you sent different books and happened to notice the one to his had a different extension, or if you sent the SAME book to both devices and they had two different extensions?


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## DYB (Aug 8, 2009)

Same book for different devices and came out in different formats.

He's had the Kindle for a while so it would need the update.  And I don't think they have the WiFi activated on the Kindle.


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## Ann in Arlington (Oct 27, 2008)

DYB said:


> Same book for different devices and came out in different formats.
> 
> He's had the Kindle for a while so it would need the update. And I don't think they have the WiFi activated on the Kindle.


That could be it, then. . . . .

You must have connected via WiFi at least once, as that is, as far as I know, the only way to actually complete the registration of the device. But I can appreciate that there might not be a network in the house where he usually uses it. So, yeah, if WiFi is generally off, the 'push' of the update would never have happened.

It can be done pretty easily manually, though -- if you're moving his books that way anyway, you won't have any problem.

But, as Leslie said, it's not really a big deal. The books will be readable either way. And most publishers aren't using any of the 'coolness' stuff of the AZW3 format so it's pretty immaterial, really.


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## GBear (Apr 23, 2009)

I just downloaded a book for both my K3 and my wife's PW. For the K3, a 515 KB AZW was sent. For the PW, a 1,974 KB AZW3 file was sent. I was very surprised to see that the AZW3 file was almost four times larger than the AZW file.

What's the "coolness stuff" in AZW3 that's taking up so much more space?

I know we're supposed to be "living in the cloud," but at half the storage and four times the file size compared to the K3, my wife will be able to store only one-eighth as many books on her Kindle than mine.


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## Mike D. aka jmiked (Oct 28, 2008)

GBear said:


> What's the "coolness stuff" in AZW3 that's taking up so much more space?


The AZW3 format is an update to the mobi format in a belated attempt to give it the same features as the ePub format has had for years. Mobi has been the "bare-bones" format of displaying text. I read the list of added features when it was announced and it included (IIRC) things like built-in support for tables and of drop-caps, etc. It also adds support CSS3 and HTML5 (these are mostly needed for video). The list of additions was quite extensive.

AZW3 still isn't as capable as ePub, but it is a step in the right direction.

The reason for the increased file size is that both the AZW and AZW3 files are contained in the downloaded book. This allows the same file to work on both old and new Kindles.

Mike


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