Rikaikun by Erek Speed
Rikaikun is a popup dictionary that helps you learn new Japanese words. When Rikaikun is enabled in Chrome, you can hover your mouse over any Japanese word or phrase and Rikaikun will pop up with its hiragana, meaning in English, and other related Japanese words.
Furigana Injector by Akira Kurogane
Furigana Injector is an awesome extension for reading Japanese web sites. The extension inserts hiragana on top of kanji to help you read it. This is great if like me, you tend to remember the meaning of a kanji but forget its pronunciation. Also, if you move your mouse over a kanji, Furigana Injector will show you its meaning in English. This saves you the effort of checking up every new kanji on the dictionary and you might even learn a new word or two with it. I noticed Furigana Injector gets some kanji names wrong, but I didn’t think it was a big deal since I’m not really trying to learn names.
Hiragana Typing by Jakub Vonsovsky
Hiragana Typing lets you type hiragana or katakana in your browser without having to use Japanese input software. I found this really useful even though I already have the Microsoft Japanese IME installed. Instead of switching back and forth between langauges when all you want is to type a few words in Japanese, you can just use Hiragana Typing.
Simply type the romaji into the Hiragana Typing box and it will automatically be converted to the correct kana. Type in lower case for hiragana and upper case for katakana.
Characterizer by fixdoodle
I find this chrome extension really interesting because it replaces the first letter of English (or other languages) words or the entire word with a Japanese kanji. This is supposed to help you remember the meaning of individual kanji characters by associating it with the corresponding word in the original language and I think it works to a certain extent. However, this is more useful for practicing kanji you’ve already learnt. You can’t really learn new kanji from it. Also, Characterizer doesn’t show the hiragana but you can always use it together with Rikaikun or Furigana Injector. I’ve tried this and I find it easier to use with Rikaikun. You can change Characterizer’s settings to limit the number of characters changed per page, whether to replace a full word or just the first letter of a word, and toggle it on or off.
Japanese Kana by Dima Budaragin
Japanese Kana is a chrome app that lets you learn hiragana and katakana right in your browser. You can choose what to test yourself on, such as basic hiragana or katakana or both. On the test page, you will be shown a hiragana or katakana and asked to pick the correct romaji from a choice of four. Immediate feedback is given after you’ve made your choice and a total score will be shown at the end of the test. A kana chart is also available for your reference. Japanese Kana does not let you hear what the kana sounds like so I would recommend this only if you’ve already learnt the Japanese phonic sounds and just need to memorize the characters.
These are the five chrome extensions/apps that I've found helpful for learning Japanese. You can find them by searching for their names in the Chrome web store.
Check out my other articles on the Japanese language: