Anki collection nearing the 100MB size limit

In the FAQ, it says that the collection size limit is 100MB of compressed data, and 250MB of uncompressed data. What does this mean? When I check my collection size on Ankiweb, it says 91.30MB. I deleted all the older decks I don’t use thinking it was going to fix it, but ultimately realized the issue is probably the card history. I have a total of 350,759⁩ reviews, which I’ve grinded over the years, and I don’t want to lose the statistics for it.

So here are my questions:

  1. As I said above, is the collection size that is stated on the Anki Web site final? As in, that number is calculated after the data is already compressed. Or do I have to check if my data is compressed/uncompressed, and if so, how do I do that?

  2. Is there really absolutely NO WAY to increase your collection size limit? I know it states in the FAQ that Anki is financed through the Apple purchase of Anki (thank you Apple users for financing this amazing project), but if given the chance, I’d be willing to pay for Anki (thought about this before even having this issue. kind of felt bad using it for free for how good it is). If possible, I’d prefer to not lose the statistics. Yeah, I know I can make a backup, and use a different unsynced account to keep the old statistics and all that, but If I’m able to keep everything as is, I’d be grateful for that.

If you’ve gone through this issue, please let me know how you went about it. Any advice is welcome. I’m sure there’s probably a better way to go about it than what I’ve thought about.


Just to make sure, did you run Check Database after you deleted the decks you are no longer using? I understand that makes some optimizations to the collection.

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Yes. I actually use the check database and check media periodically. I’m on an older version of Ankidroid and Anki (due to reasons), which messes up the new cards order when switching between them due to a bug in Ankidroid, so I have a habit of doing so every time I switch devices.

Thanks for confirming. I have 138,920 reviews and AnkiWeb reports my collection is 4.63MB. That is about 40% the number of reviews compared to yours but only 5% the space, so I think something else is going on. The remaining decks may be very heavy in content perhaps. I’ll be interested to hear what others suggest.

Welcome to the forum, by the way!


Oh wow, if there’s such a massive difference, then it’s gotta be the remaining decks being really heavy and not the review history, which is worse in my case since aside from a collection size limit increase, there’s no alternative other than completely changing the way my decks are structured. It did go through my mind at one point that that may be it, but I used an extension to do HTML stripping of all my decks, since one of them in particular (which uses a digital dictionary to import data via Ankiconnect) has some HTML formatting in 1 field, but it didn’t really show that much difference and thought “it’s probably not it”, but yeah, it’s most likely the decks being really heavy at the end of the day unfortunately.

Thank you for the info and being so helpful. I won’t click on the “solution” button for a bit in case it closes the thread, just in case someone else wants to chime in and say something else.

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Small update:
I completely erased the contents of 1 field out of 8000+ older cards (I no longer use that field for mature cards, only when they’re fresh) which was the potentially heaviest of them all, and noticed pretty much 0 difference in collection size.

I then went on to make an Anki collection package backup (without media) of all my current decks, and the final file size is: 19.6MB. (the compressed/uncompressed question applies here as well. I assume this is compressed size?)
Pretty heavy, but not anywhere close to the 91.30MB which I still have on Ankiweb.

Something is just weird. It can’t be that the reviews history takes that much size, since garrettm30’s comment contradicts that, but at the same time what else could it be? Does Anki keep a history of all the changes you make? Or maybe the “find and replace” ones? Because I did some mass changes via regexps on 10+ thousands of cards, multiple times, totaling maybe 40k changes. What about the scheduling? I have an addon that I use once in a blue moon that changes the scheduling of cards (taking a vacation/skipping a day/optimizing the scheduling of future cards so as to not get days with a bunch of cards/etc.). How about change of ease value via addons? Is any of that archived in Anki?

Is the size of the collection shown on AnkiWeb the compressed size?
I expected its uncompressed size, so I thought it could hold about 150MB more.
(If so, I only have 9MB left!)

I’m sure we can resolve this issue. Probably Damien will come around and tell us what we need to know, but I have found a couple of ideas that we might end up trying:

  1. Force a one way sync to AnkiWeb (choose upload). Damien suggested it here: Size of my collections - #9 by dae

  2. I understand that review history of deleted cards is still retained so that you have accurate stats. It looks like you can get around that by exporting to a new profile. I learned this here:
    I have 10 cards in collection, but the collection size is 300MB

There is no harm in trying idea # 1 (make sure everything is in sync, and then force a one-way sync from the device that you are sure is up-to-date and choose “upload”), but I would wait a bit before trying the second idea to see if we get better guidance. As you said, so far it does not seem that review history is the main problem.


Is the size of the collection shown on AnkiWeb the compressed size?

I have wondered this as well. @dae As a little suggestion, maybe you could consider making AnkiWeb give the upper limit, such as “91MB (of 250MB max)” or some such. We are curious about compressed versus uncompressed, but I think the main thing we want to know is just how close we are getting to the limit.

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I tried #1, and it got my collection size down from 91.30MB to 69.88MB. Way better.

Maybe that was all the stuff I deleted now actually getting updated? The number still seems a bit high. As for #2, I’ll take your advice and wait for a bit.

Thank you again, garrettm30.

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I’ve logged this on Show xx of 250MB on AnkiWeb · Issue #3017 · ankitects/anki · GitHub

After deleting content, you need to 1) use check database and then 2) force a full sync in order for the space to be freed from AnkiWeb. The limit is 250MB, and if you don’t have a millions of previous reviews, chances are the majority of the space is taken up by large text content in the fields (or verbose HTML formatting).


I guess that clears things up. It’s still going to be pretty close since I’ll very likely triple my current decks size in the next couple of years, but that’s for future me to worry about I guess. Maybe by then we’ll have a paid version for heavy users/people who want to support Anki with less limits and all that. But just to make extra sure: Is there anything archived by Anki that could “accumulate” so-to-speak, aside from decks/cards and the previous reviews?

Also, correct me if I’m wrong (saw this on a reddit message) since I’m not a very tech savvy person. When I did an Anki collection export in .colpkg format without media, the file created was 19.6MB. My current collection size on Anki web is about 70MB. Given that the Ankiweb size is uncompressed, and the .colpkg is apparently compressed, would that look about right to you? Just eyeballing it. No need to think too deeply about it.

Oh yeah, thank you both for your time, and sorry for making a fuss about it. I just kept seeing the number go up, and couldn’t ignore it any further.

(Gonna click on the “Solution” button after this.)


A ~4x compression ratio is not that unusual - text and HTML usually compresses pretty well.


Perfect. Thank you both again very much. I’ll get back to grinding then knowing I still have a lot of time left.


Really interesting thread! One thing that I wanted to mention, @CollectionSize1000, is that you can actually run your own synchronisation server. I don’t know what your appetite for self-hosting is (it can get pretty technical at times), but it’s an option if AnkiWeb doesn’t increase their limit faster than you can use it up :slight_smile:

Hmm, I wonder what AnkiWeb says for my account…

Collection: 3.48MB Media: 1.68MB

…I think it’ll be a while before I need to think about this for myself! :upside_down_face:


Glad you found it interesting at least.

While I’ve not looked into the specifics of it all, I’m aware of the self-hosting option. I’d like to avoid it as much as possible though. I don’t really see myself buying a home server for a long time (nor want the responsibility in managing one), and while renting one is an option, I’d much rather that money go directly to the Anki project if possible.

I’ve looked into different ways of reducing collection size, and found a couple of places where I can save some space, so hopefully it won’t become an issue in at least 4-5 years, fingers crossed.

Thanks for the heads up, though.

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