Spaced Repetition Schedule Calculator
Enter when you start learning and how many word groups you plan to study. Get a day-by-day review timetable based on the Ebbinghaus forgetting curve — exportable to your calendar.
One group = one day of new material, e.g. 20 words
Why these intervals? The forgetting curve
How the classic 40-day review plan works
The classic plan reviews each new group 1, 2, 4, 7 and 15 days after learning. Study one group a day for 25 days and the final review lands on day 40.
The short early intervals catch the steepest part of forgetting; the later gaps widen as successful recall strengthens the memory.
This spaced repetition calculator makes a fixed timetable for paper study. An FSRS app instead schedules every card from what you actually remembered, so it can adapt when a review feels easy or hard.
FAQ
What is a spaced repetition schedule calculator?
It turns a start date, number of study groups, and a review-interval preset into a day-by-day timetable. This calculator can generate a fixed 40-day plan; an adaptive FSRS app adjusts each card from your recall instead.
How do I export a review timetable to my calendar?
Generate the timetable, then choose “Export to calendar (.ics)”. Open the downloaded file in Apple Calendar, Google Calendar, Outlook, or another calendar app that supports ICS files.
What are the best spaced repetition intervals?
A practical schedule reviews each item 20 minutes after learning, then 1 day, 3 days, 1 week, 1 month, and 3 months later. After about six well-timed reviews, material is effectively in long-term memory. The exact optimum varies per person — that is what adaptive algorithms like FSRS solve.
Why review 20 minutes after learning?
The forgetting curve is steepest right after learning: about 42% is forgotten within 20 minutes. One quick review in that window flattens the curve dramatically and makes every later review cheaper.
What is the classic 40-day plan?
The textbook Ebbinghaus plan reviews each group 1, 2, 4, 7 and 15 days after learning it. If you learn 25 groups on 25 consecutive days, the last review lands on day 40 — hence the name.
Do I still need this table if I use an SRS app?
No — that is the point of SRS apps. KaChiKa and Anki schedule each card individually based on your actual recall, which beats any fixed table. This calculator is for paper-based studying or understanding how spaced repetition works.
