How Many Flashcards Should You Study Per Day?

The short answer

For most people building a long-term deck: 10–20 new cards per day, plus however many reviews fall due. The new-card number is the one you choose; the review number is the one the system chooses for you — and it’s the review number that determines whether this is sustainable.

That second half is what most “study X cards a day” advice leaves out.

Why the review count is the real budget

Spaced repetition works by showing you a card again just before you’d forget it. Every new card you add today schedules a chain of future reviews — tomorrow, in a few days, in a couple of weeks, and so on, with the gaps widening each time you recall it successfully (the spacing effect, first measured by Hermann Ebbinghaus in 1885, and replicated continuously since).

The consequence: new cards are a loan you repay in reviews. Add 20 new cards a day and, once your deck matures, you can expect roughly 150–200 reviews a day just to keep them alive — the exact ratio depends on your retention settings, but the multiplier is real and it surprises people about three weeks in, which is exactly when many quit.

So the honest framing isn’t “how many cards can I learn today?” It’s “how many reviews can I commit to every day for the foreseeable future?” Pick the new-card rate that keeps the review load inside your daily time budget.

A simple way to choose your number

1. Estimate your daily time. Be honest — the sustainable number is the one you’ll still do on a bad day. 15 minutes is plenty to start.
2. Budget ~5–8 seconds per review card. 15 minutes ≈ 120–180 reviews/day.
3. Set new cards to a fraction of that. Starting at 10/day and raising it once the review load settles is far better than starting at 50 and drowning.

If you’re cramming for a fixed date rather than building permanent knowledge, the maths flips — front-load new cards and accept lower long-term retention. For anything you want to keep, steady and small wins.

The mistake to avoid

The classic failure isn’t studying too few cards — it’s adding too many new ones early, watching reviews pile into an unmanageable backlog, and abandoning the deck. A backlog is demoralising precisely because the system is working as designed: those reviews are the cards you’d otherwise be forgetting.

If you ever face a wall of overdue reviews, don’t try to clear it in one sitting. Lower (or pause) new cards until the backlog drains, then resume.

Want to put this into practice without the spreadsheet maths? cardagain handles the scheduling for you — you choose how many new cards to see, and it surfaces reviews exactly when they’re due.