How to use the flashcard repetition calculator
This page works out how many times you need to go through a deck to reach a target recall rate. Enter the number of cards, the recall you are aiming for, the share of still-unlearned cards you typically pick up in one round, any rounds you have already done and your review time per card. It returns the repetitions needed, the recall that lands you at, and the card reviews and time still ahead of you.
The model assumes the unlearned pile shrinks by a fixed share each round. At 50% learned per round you are at 50% after one round, 75% after two and 87.5% after three, and the tool rounds up to the first round that clears your target. Set the per-round scope to unlearned cards only and the workload shrinks as you go; set it to the whole deck and it stays flat. The formula used is printed with the results.
There is no validated constant for how much a single repetition retains, so the learned-per-round share is an assumption you supply and the output is that assumption extended, not a prediction. The page does not schedule review dates, and it does not model differences in card difficulty or the forgetting that happens between rounds.
Frequently asked questions
You supply it as an assumption. There is no validated constant for retention per repetition, so the most realistic approach is to count how many new cards you actually learned in your last round.
The model shrinks the unlearned pile by a fixed share each round, so it never reaches 100% in a finite number of rounds. Targets are therefore limited to 1-99%.
No. This page only handles the number of repetitions and the workload each one carries. For the days between reviews, use a spaced-repetition interval calculator instead.