All online German dictionaries include a few options and features that make them unique and more helpful than others in certain situations. It is important to first identify what you need and how you plan to use the online dictionary, so you can choose the correct one. I use each of the dictionaries listed here for different reasons.
Dict.cc

My go-to online German dictionary is dict.cc. If I need to look up a word or even a short phrase, this is my first stop. It includes more words, word combinations and phrases than any of the other dictionaries on the list. Simply stated, it is the most complete dictionary on the list. It even includes obscure idioms and colloquialisms that you won’t find in any other dictionary on the list.
While in Germany using the mobile app is highly recommend. You can download the entire language pack and never use data while using the app. This will definitely come in handy while traveling. I did this on my last trip to Germany and it was fantastic.
LEO

My go-to online dictionary for a long time (before discovering dict.cc) was LEO. It includes most of the words and phrases you will need, but there have been a few times that I couldn’t find what I was looking for on LEO. It is still a pretty handy dictionary and it includes audio samples like a lot of other dictionaries.
One of the key advantages of LEO is the mobile app. It doesn’t allow you to download the language pack like dict.cc, but it does work flawlessly. When in class I often use it when a student who asks for a word that I don’t know (which happens way more often than it should). It is a quick, light mobile app with a great user interface. It is available on Android, iOS, and Windows Phones.
You can even integrate it directly into your web browser, which allows you to find any word on any website without leaving the site. If you do a lot of online reading in German, but often find yourself opening a dictionary in another tab, this is the feature for you.
I have a more complete review of the LEO online dictionary and all of the other features available on their site. It is several years old, but pretty much all of the information is still correct.
Linguee

This is a different kind of dictionary entirely. I use this almost every time I write a video script. In addition to the usual word-to-word and phrase-to-phrase translations, Linguee shows you results of the word or phrase for which you are searching as it is used in articles and websites around the internet.
If you want to make sure that you are using a word correctly or to confirm that a certain phrasing is more common than another, just type it into Linguee and read a few of the results. If there aren’t any results for exactly the phrase you typed in, assume that it either can’t be phrased that way or simply shouldn’t be. Sometimes you will even find a usage of a word that you didn’t know was possible.
The Linguee app is available on Android and iOS and works perfectly. It is exactly the same as the online version and you can even use it offline, so you don’t eat up your data allowance on your mobile device. This is a dictionary app like no other. It is a must have for anyone who is really serious about learning the more intricate details of the German language.
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