Find how many flashcards you can review in a study session.
Flashcard throughput is not simply the session length divided by a fixed card time, because difficult cards dominate the clock. Weighting the easy and hard proportions by their respective times gives a true average — with a quarter of cards taking two and a half times longer, the average is nearly forty percent above the easy-card figure, which is exactly why deck sizes that look manageable overrun.
Weighted card time
Average seconds = easy seconds x (1 - difficult share) + easy seconds x multiplier x difficult share
Throughput
Cards per hour = 3600 / average seconds per card
Two hundred to four hundred for mature, well-known cards, dropping to well under a hundred for new material where each card needs genuine thought. Spaced-repetition software reports your real rate.
Yes, and that is precisely what spaced repetition automates. Cards you fail return sooner, which concentrates time where the learning gap is.