Humans forget newly learned material in a matter of days (red curve) unless reviewed from time to time (red arrows pointing up).
Repeating reviews has the effect of slowing down the rate at which you forget (green curves).
Humans remember things more effectively when reviews are spread out over time
than when reviewed many times in a short period of time.
Wikipedia .
Spaced repetition is a learning technique in which items are reviewed in increasing intervals of time
to make maximum use of the spacing effect so that they can be remembered effectively and efficiently.
It is known to be especially well suited for memorizing huge amounts of material and keeping them indefinitely in memory.
Wikipedia .
See how well you're keeping up with your reviews at a glance with various statistical charts.
No installation. No synchronization between devices. Directly access your cards from a browser on an Android, iPhone, tablet, Mac, or PC.
Create your own decks to memorize anything from foreign languages to maps and chemical symbols. Or simply select a deck from the official decks list, which includes decks for the world map, Japanese Kanji, and more.
The key to memorization is repetition. Use your smartphone or laptop to review your cards in your spare time anywhere, any time.
With Spaced Repetition, you spend time reviewing items that need it, not on the ones you have memorized. Efficiency by spending the minimium time required to keep things memorized is crucial when memorizing huge amounts of information, in areas such as:
Handwrite your answers directly on screen to precisely test your memory and to help you memorize better. Keyboard input is also supported.
Add images to your cards to memorize maps, pictures, and drawings. Create links to images on external sites or upload your own images.
Card content recognizes Markdown, a simple yet powerful markup language, allowing you to create cards with links and text formatting..
Multiple-choice cards can also be created in addition to standard frontside-backside cards.
Creating cards may take time. If you have cards in another system or wish to create cards with other software such as Google Spreadsheet or Excel, simply import them as a CSV file.
Receive notifications when you have cards due for review by setting the time of day at which you wish to be notified.
Do last-minute reviews immediately before exams using a special mode for reviewing only the worst-performing cards.