How to use the spaced repetition timing calculator
Ebbinghaus's forgetting curve showed that memory drops fastest right after studying, which is why widening the gap between reviews is generally more efficient than repeating at a fixed interval. The specific schedules quoted everywhere, such as "1 day, 7 days, 30 days", do not come from Ebbinghaus's original work. The best spacing depends on the material, its difficulty and the learner, so this calculator does not impose a schedule: you set the first gap and the multiplier yourself.
Enter the first review gap, the gap multiplier and how many reviews you want, and the calculator builds a table of which day after studying each review falls on along with the gap since the previous one. Each gap is the previous gap multiplied by your multiplier, so a first gap of 1 day with a multiplier of 2 accumulates as day 1, day 3, day 7, day 15. A multiplier of 1 simply repeats the same gap. Days are shown rounded to whole days.
Add the days remaining until your exam and the calculator also reports how many reviews actually fit and how long before the exam the last fitting review lands. A review that falls exactly on the exam day still counts as fitting and is labelled as being on the exam day itself. If the plan overshoots, it tells you how many reviews spill past the exam so you can lower the multiplier.
This calculator works out timing only; it does not predict recall rates or scores. Treat it as a way to lay out a schedule you have chosen, not as a source of one correct schedule.
Frequently asked questions
No. It is widely quoted but it does not come from Ebbinghaus's original work and it is not a verified optimal schedule. Set your own gaps.
The gap stops growing and the same number of days repeats. Use it when you want a steady interval such as daily review.
Yes. Anything up to and including the exam day counts, and a review on the exact day is labelled as being on the exam day itself.