Website for checking text difficulty

I created a website for checking Japanese text difficulty:
You can paste a text of your choice (song lyrics, news article, wikipedia article) and you will get a bunch of interesting numbers and charts in return. It uses kanji frequency data so you may see what part of kanji are common ones. You may also provide your WaniKani API v2 key to get additional information (e.g. what part of kanji in the text you already know according to WaniKani).
Feedback and ideas for improvement are very much welcomed.

Example screenshots:


Ohh… That’s a brilliant site. It let’s me know one important thing, when using my API:

OMG I need to study… :sweat_smile:

Definitely bookmarked this though for later use. :grinning:


You’re on level 1 so 頑張って :slight_smile:

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This is great! Really love how the site looks, and the data is awesome.

I noticed a couple of small formatting issues when displaying the site on mobile, so might want to check those out! I’m happy to provide screenshots if you want :).

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Thank you!
The website has not been thoroughly tested and I didn’t aim to be pixel perfect but I would appreciate screenshots, maybe that would be something I can easily fix.

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These are all reproducible in Chrome!

“kanji frequency data” overlaps back button

tooltip gets cut off along right edge


Also, it’d be nice if all external links that lead off of the site opened in a new tab! Just a thought. I tested the site in Safari, Firefox, and Chrome on my mac and outside of the issues above it looked good :).


Super awesome!

This works (AFAIK) in Chrome with a Iorem ipsum-like generated text:

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Wow, thank you for screenshots and suggestions. I believe all your suggestions are fixed now!


My pleasure! And yep, looks like they’re all fixed! Great!


Wow! This is amazing! I will use this for everything from now on. :open_mouth:


Very cool site! Are you planning to add something to show which kanji you havent learned on WK? I’ve learned hundreds of non-wk kanji elsewhere, so the whole %known isn’t as applicable to people like me. Would give us a chance to see what we actually dont know. Also theres a show more tab, but would a “show less” also be possible? That way I can look through as many as I want, but not worry about having a non-removable giant wall of kanji.


@halfriver Pretty graphs and numbers :3


Amazing, what a great idea you had! thanks for it, I’m bookmarking this site!


Thank you for sharing!! :grinning: Definitely will use this. :heart:

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Looks nice! Bookmarked.

Side note

Side note:
“Accumulate” is a verb.
“Cumulative” is the correct form for adjective, So, “Cumulative Frequency”.


That seems really useful. Think it’ll get me to sit down and read some.

Wow, I like that.

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interesting. The WaniKani connectivity is even more useful. Good job.

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Thanks a lot for a positive feedback! It definitely boosts my motivation.

@rfindley Thanks for spotting this and letting me know. Fixed.

@Vanilla Good suggestions, thank you.
Regarding “show less” idea: I decreased number of kanji that are shown by default from 100 to 30. It should answer this.
As for WaniKani suggestions: I improved the section. Now you can see the list of non-WK kanji (and not only this). You can also mark selected kanji as “learned” and this is instantly reflected in affected charts/numbers. The selection of “learned” kanji is cached, will work after page refresh or for different text. Please have a look and let me know if this makes any sense to you.

Happy to hear further ideas.



Yep, looks good to me. Thanks!