Spaced repetition
Six boxes decide when each word comes back
Every word you learn sits in one of six boxes. Know it, and it moves to a box you review less often, up to about once a month. Miss it, and it drops back one box so you see it sooner.
Try it below: rate five real Spanish cards and watch where each one goes.
- Free
- Works for lessons and your own decks
- 0New & missed
- 1Daily
- 2Every 3 days
- 3Weekly
- 4Every ~2 weeks
- 5Monthly
el gato
cat
How well do you know this word?
The six boxes and how often you see them
These are the real intervals the app uses. Box 0 is where new words start and where missed words land, and Box 5 is for words you know well.
- Box 0 New & missed Every day Words you just learned or just missed
- Box 1 Daily Every day Still settling in
- Box 2 Every 3 days Every 3 days Starting to stick
- Box 3 Weekly Every 7 days You mostly know it
- Box 4 Every ~2 weeks Every 16 days Well known
- Box 5 Monthly Every 35 days Long-term memory
Four answers, four different moves
After each card you pick how well you knew it. Being honest here is what makes the schedule work: Hard and Don't Know are there so a shaky word gets more practice, not as a penalty.
| You tap | The word | Next review |
|---|---|---|
| Don't Know | Down 1 box (never below Box 0) | Tomorrow |
| Hard | Stays in its box | In 2 days |
| Know it | Up 1 box (up to Box 5) | On the new box's schedule |
| Easy | Up 2 boxes (up to Box 5) | On the new box's schedule |
One word, 4 reviews, two months
Say you learn a word, it lands in Box 1, and you tap Know it every time it comes back. Here's its schedule. After the review on day 27 you won't see it again for 35 days.
- Day 0Learned in a lesson, goes to Box 1
- Day 1 Review: Know it, moves to Box 2
- Day 4 Review: Know it, moves to Box 3
- Day 11 Review: Know it, moves to Box 4
- Day 27 Review: Know it, moves to Box 5
- Day 62 Next monthly check
Want the research behind spacing out reviews? Read the science behind Flashcardly.
Questions people ask
What is the Leitner system?
A way of scheduling flashcards published by Sebastian Leitner in 1972. Cards live in boxes: the better you know a card, the higher its box and the less often you see it. Flashcardly uses six boxes, from every day up to about once a month.
Do I have to plan my reviews?
No. The app keeps track of every word and shows you the ones that are due. You just answer.
What happens when I forget a word?
Rate it Don't Know and it drops one box and comes back tomorrow. It doesn't go all the way back to the start, so a word you knew for weeks recovers quickly. Hard keeps it in its box and brings it back in 2 days.
Are reviews free?
Yes. Reviews and repeating lessons are unlimited on every plan.
Does it work for my own decks too?
Yes. Cards in your own decks, including AI decks, go through the same six boxes with the same intervals.
Something else? See the support page or ask us.
Works well with
Lessons
184 lessons per course in five-minute parts, each word with a real picture and native audio.
Custom decks
Type a word and our dictionary of about 6,000 words fills in the picture and audio.
Practice modes
Word Match, Audio Match, Sentence Builder and Type It Out, free with your lessons.
Let the app decide when to review.
Free on iPhone and Android. Try a sample lesson before you even sign up.
Scan with your phone's camera to get the app.
