Spaced Repetition Calculator
Plan your flashcard study schedule.
Enter total cards and daily new cards to see how long it takes and what your review load looks like.
How Flashcard Study Time Is Calculated
Effective flashcard study relies on spaced repetition — reviewing cards at increasing intervals based on how well you know them. The estimated study time depends on deck size, card difficulty, and your review schedule.
Daily Study Time Formula:
Time (sec) = (New Cards × 30) + (Review Cards × 8)
Where:
- New Cards = cards being seen for the first time today
- 30 sec = average time to learn and process a new card
- Review Cards = cards due for review based on past performance
- 8 sec = average time for a mature card review
Those two numbers are what the calculator below uses, and they assume short, well-made cards that ask one thing each. Dense cards run three or four times longer. If your deck is full of paragraph-length answers, take the figure the calculator gives you and multiply it, then go and split the cards up, because the long ones are also the ones you will keep failing.
Spaced Repetition Intervals (SM-2 Algorithm):
- First correct answer: review in 1 day
- Second correct answer: review in 6 days
- Third: ~15 days
- Subsequent: multiply by ease factor (~2.5 for easy cards)
Worked Example: You add 20 new cards/day to a medical vocabulary deck. At steady state, roughly a month in:
- 20 new cards × 30 sec = 10 min
- ~160 reviews × 8 sec = 21 min
- Total: ~31 min/day
The review count is the part people get wrong. Each new card comes back around eight times in its first couple of months, so twenty new cards a day settles at something near 160 reviews a day, not twenty. That ratio is why the daily load feels fine in week one and crushing in week five, and it is the single most common reason people abandon a deck.
Practical Guidelines:
- Anki recommends no more than 20–30 new cards per day for sustainable learning
- A 1,000-card deck takes roughly 3–4 months to fully mature with 20 cards/day
- Retention rate with spaced repetition: ~90–95% at test time
- Short daily sessions (30–45 min) outperform 3-hour weekend cramming sessions
- Morning review after sleep leverages memory consolidation during REM sleep
How we build and check this calculator
This calculator runs entirely in your browser, so the numbers you enter stay on your device. The math behind it is written by hand and tested against worked examples and standard references before the page goes live.
SuperGlobalCalculator is independently built and maintained. See how we build and verify our calculators.