How Spaced Repetition Works
Understand the science behind Repeatica's review scheduling algorithm.
Spaced repetition is a learning technique that schedules reviews at increasing intervals based on how well you know each piece of information. The harder something is to remember, the more frequently you review it. The easier it is, the longer you wait before seeing it again.
The core idea
Our memory fades over time — but reviewing information just before you're about to forget it makes the memory stronger and lasts longer. Spaced repetition automates this by tracking your performance on each flashcard and calculating the optimal time to show it again.
Repeatica's algorithm
Repeatica uses a variant of the SM-2 algorithm, the proven foundation behind spaced repetition systems since the 1980s.
When you rate a card during review, the algorithm adjusts two values:
- Interval — How many days until the next review
- Ease factor — How easy the card is for you (affects future intervals)
Rating → interval change
| Rating | Effect |
|---|---|
| Again | Card resets; shown again soon (short interval) |
| Hard | Interval increases less than normal; ease decreases slightly |
| Good | Interval increases normally |
| Easy | Interval increases more than normal; ease increases slightly |
New vs. review cards
- New cards — Cards you've never seen; shown during review when you have remaining new card quota for the day
- Review cards — Cards due today based on their scheduled interval
- Learning cards — Cards answered "Again" recently; shown in short relearning steps
What "due today" means
Each card has a due date. When you open the Review screen, you see all cards whose due date is today or earlier. As your card count grows, Repeatica spreads them across days automatically — you won't see hundreds of cards on one day.
The long-term payoff
A card rated "Good" consistently will have an interval that grows to weeks, then months. You'll only see it a handful of times per year — but it'll stick.