What is Spaced Repetition?

The spaced repetition system or spaced repetition algorithm is a vocabulary learning technique that helps you memorize vocabulary for the long-term. The algorithm increases the time intervals between the review sessions until you can effortlessly recall the word. The time interval gets increased only if you are able to correctly recall the word.

The basic idea is that as the intervals between reviews increase, it makes it a bit harder for you to recall the word. You challenge your brain and try to remember. This process of active recall strengthens the memory.

kwiko - spaced repetition and brain workout

What is Active Recall?

Spaced Repetition encourages active recall. Active recall is the process of retrieving information from your memory

As an example, imagine you want to stop by a bakery in Berlin and want to buy a loaf of bread. Before you even approach the shop, you remember that bread in German is ‘das Brot’. This is an example of an ‘active recall’.

Alternatively, if you approached the shop and saw a sign ‘das Brot’, this would count as a ‘passive recall’. You saw the word and then matched its meaning.

kwiko app - active recall vs passive recall

A passive recall is much easier and creates a false sense of learning. However, recognizing a word when you see it doesn’t mean you are able to use it in dynamic, real-life situations, such as a conversation with a colleague. That’s why multiple-choice matching games in some language learning apps are fun but often waste your time.

Vocabulary apps that use the Spaced Repetition system


Anki popularized the technique among memory experts and language learners. The software digitally mimics the flashcard experience. It’s open-source software available on desktop and mobile. There are many third-party mobile apps based on Anki’s open-source infrastructure and most of them are very poor quality. The usable ones are expensive.


kwiko is a German vocabulary learning app. The app uses a Spaced Repetition system as its core learning mechanism.

We do our best to keep the design simple, user-friendly, and pleasant. kwiko is available for free on iOS and Android.

kwiko app uses Spaced Repetition Algorithm

Learn more about Spaced Repetition

  1. Wikipedia article
  2. Intro to Spaced Repetition for vocabulary learning – YouTube video by 5-minute language
  3. Here is another video primer from a memory improvement YouTube channel.

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