Spaced repetition calculator
See when a flashcard comes back after each answer. Rate a new card Good every time and FSRS brings it back after 10 min, 2 days, 11 days and then 2 months.
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Pick the buttons. I'll do the date maths.
When will my flashcard come back?
Add a rating for each review, or pick an example. Each review happens on the day the card is due. The gaps come from the same scheduler the app uses, with fuzz (small random shifts) turned off.
The share of cards you should still remember when they come back. The app uses 90%.
After review 6, the card comes back in 1 year: 2 years after you first studied it.
- 1GoodBack in 10 min10 min since first seen
- 2GoodBack in 2 days2 days since first seen
- 3GoodBack in 11 days13 days since first seen
- 4GoodBack in 2 months2 months since first seen
- 5GoodBack in 5 months7 months since first seen
- 6GoodBack in 1 year2 years since first seen
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Save my remember % in the app
Shows the 90% you picked on My progress and the Flashcards screen. Your reviews still follow the app's 90% target. No account needed.
How does target retention change the gaps?
Target retention is the share of cards you want to still remember when they come due. 90% is the app's setting. Asking for more means shorter gaps and more reviews. Below: a card rated Good every time.
| Review | 80% target | 85% target | 90% target | 95% target |
|---|---|---|---|---|
| After review 1 | 10 min | 10 min | 10 min | 10 min |
| After review 2 | 8 days | 4 days | 2 days | 1 day |
| After review 3 | 3 months | 1 month | 11 days | 3 days |
| After review 4 | 1 year | 6 months | 2 months | 8 days |
| After review 5 | 8 years | 2 years | 5 months | 19 days |
| After review 6 | 32 years | 8 years | 1 year | 1 month |
How does the calculator work?
FSRS (Free Spaced Repetition Scheduler) keeps two numbers for every card. Stability is how many days it takes for your chance of remembering to fall from 100% to 90%. Difficulty is how hard the card is for you. Each rating updates both, and the next review lands on the day your chance of remembering drops to the target.
- Again means you forgot. The card comes back within minutes and its stability drops.
- Hard, Good and Easy mean you remembered. Each one grows stability by a different amount, so the gaps grow too.
- A brand-new card first goes through short learning steps (minutes), then moves to days.
- These numbers use FSRS's default settings. Tools that tune FSRS to your own review history, like Anki's optimizer, will give you different gaps over time.
- No gap is ever longer than 100 years, the scheduler's built-in cap, which is why low targets top out there.
Want the longer story, including how FSRS differs from older schedulers? Read spaced repetition explained or see how the app schedules your cards.
Try it with today's mission.
Open the app and spend 20 minutes on a free subject or your own notes. Start without signing up, no card needed.
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