Flashcard Statistics: Anki, Quizlet and What Research Says

Quizlet says more than 60 million people use it, and the free Android version of Anki, AnkiDroid, shows 10M+ downloads on Google Play. On whether flashcards work, the cleanest evidence comes from Kornell (2009): studying one big stack of flashcards beat studying several small stacks for 90% of participants, even though 72% believed the opposite after their first session.

Below are 50 flashcard statistics, each checked against its primary source in September 2026: app store listings and company press releases for usage, peer-reviewed papers for effectiveness, and our own dataset of 18,217 flashcard reviews.

Key statistics

AnkiDroid, the free Android client for Anki, showed 10M+ downloads and a 4.7-star rating from 165K reviews on Google Play (checked September 28, 2026).
Quizlet says more than 60 million students, teachers and everyday people use its platform, including 2 in 3 US high school students and 1 in 2 US college students (Quizlet press releases, 2025 and 2026).
Quizlet's iPhone app had about 1.12 million ratings on the US App Store, averaging 4.8 stars, compared with 2,342 ratings for the $24.99 AnkiMobile app (checked September 28, 2026).
Spacing flashcards in one large stack was more effective than studying small stacks for 90% of learners, yet 72% believed the small stacks had worked better (Kornell, 2009).
40.1% of 177 college students listed flashcards as a study strategy, but only 6.2% named them their top strategy (Karpicke, Butler and Roediger, 2009).
Almost 70% of 415 introductory psychology students used flashcards for at least one exam (Golding, Wasarhaley and Fletcher, 2012).
64% of 472 undergraduates said they would put aside material once they felt they knew it, a habit that lowered recall in flashcard experiments from 63% to 59% (Kornell and Bjork, 2007).
Each additional 1,700 unique Anki cards was associated with one more point on USMLE Step 1 in a study of 72 medical students (Deng, Gluckstein and Larsen, 2015).
In 18,217 reviews by 667 StudyCards AI students, accuracy on the same card rose from 69.0% on the first attempt to 97.7% by the fourth (StudyCards AI, 2025 to 2026).
Study sessions on decks of 50+ cards were completed 7.8% of the time, versus 25.0% for decks of 10 cards or fewer (StudyCards AI, 1,593 sessions).
The open-source FSRS benchmark is built on about 727 million Anki reviews from 10,000 users (open-spaced-repetition, srs-benchmark).

How many people use Anki and Quizlet?

Quizlet is far larger by any public measure: it reports 60 million users, while Anki publishes no user count at all and the best proxy is AnkiDroid's 10M+ install band on Google Play.

All app store figures below were read from the official listings on September 28, 2026. Google Play shows downloads as ranges ("10M+" means somewhere between 10 million and 50 million lifetime installs), not active users. Apple ratings are per storefront, so the US counts below understate global totals.

Official app store figures for Anki and Quizlet, checked September 28, 2026
App	Store	Downloads	Rating	Ratings or reviews	Price
AnkiDroid	Google Play	10M+	4.7	165K reviews	Free
AnkiMobile	App Store (US)	Not disclosed	4.0	2,342 ratings	$24.99
Quizlet	Google Play	50M+	4.7	917K reviews	Free, in-app purchases
Quizlet	App Store (US)	Not disclosed	4.8	1,122,825 ratings	Free, in-app purchases

Quizlet says it reaches 60 million students, teachers and everyday people, including 2 in 3 US high school students and 1 in 2 US college students. The figures appear in its July 2025 How America Learns release and again, as "over 60 million", in its August 2026 product release. These are company claims, not audited figures.
That August 2026 release also announced a spaced repetition mode for Quizlet, the scheduling approach Anki is built around.
The main Anki repository on GitHub, ankitects/anki, had 31,641 stars and 3,281 forks on September 28, 2026. The GitHub repository dates from December 2012.
The community-built Android client, AnkiDroid, had 11,874 GitHub stars and is licensed under GPL-3.0.
The SRS Benchmark used to test Anki's FSRS scheduler draws on about 727 million flashcard reviews from 10,000 Anki users (9,999 collections in the published results). It is the largest public flashcard review dataset we know of.

Myth check: "Anki has X million users"

You will find confident Anki user counts on stats roundup sites. None of them has a primary source. Ankitects, the company behind Anki, does not publish active users, desktop downloads or AnkiMobile sales. The only official number is AnkiDroid's Play Store band, which counts lifetime installs of one client, including people who installed it once and never opened it again.

The same caution applies to Quizlet. Its releases say 60 million people "use" Quizlet without saying whether that means per month, per year or ever. Treat any "60 million monthly active users" claim as a paraphrase that goes beyond what Quizlet has said.

For a feature-by-feature comparison of the two apps, see our Anki vs Quizlet breakdown. If you are setting Anki up for the first time, our guide on how to download Anki on every platform covers which versions are free and which are paid.

What Anki's own documentation says about workload

Anki's manual gives the most useful planning number for any flashcard user: 20 new cards a day turns into roughly 200 reviews a day.

"If you are consistently learning 20 new cards a day, you can expect your daily reviews to be roughly about 200 cards/day," according to the Anki manual's deck options page. That is a 10 to 1 ratio of reviews to new cards.
With the FSRS scheduler, Anki's default desired retention is 90%. The manual warns that above 90% "the workload increases very quickly, and above 97% the workload can be overwhelming."
Under the older SM-2 scheduler, the default starting ease is 2.50, meaning each correct "Good" answer multiplies the gap before the next review by about 2.5 (Anki manual).

The research behind those schedules is covered in our spaced repetition statistics page.

How many students use flashcards?

Somewhere between 40% and 70% of college students use flashcards, depending on how the question is asked, but few treat them as their main strategy.

40.1% of 177 undergraduates at Washington University in St. Louis listed flashcards among their study strategies, making them the third most common after rereading (83.6%) and practice problems (42.9%). Only 6.2% ranked flashcards as their number one strategy, against 54.8% for rereading (Karpicke, Butler and Roediger, 2009).
Almost 70% of 415 students in an introductory psychology course used flashcards to study for at least one of three exams (Golding, Wasarhaley and Fletcher, 2012).
56% of participants in Kornell and Bjork's flashcard experiments said they used flashcards to learn, and 75% of those said they drop cards, setting some aside to spend more time on others (Kornell and Bjork, 2007).
In a survey of 472 UCLA undergraduates, only 9% said they usually do not quiz themselves (with flashcards, practice quizzes or end-of-chapter questions). 68% said they self-test to check how well they have learned something, and just 18% saw testing as a way to learn (Kornell and Bjork, 2007).
A survey of 374 undergraduates found that students understand the value of practicing flashcards to a higher criterion but "do not typically implement or understand the benefits of practising with longer lags" (Wissman, Rawson and Pyc, 2012).

Do flashcards work? What the research says

Flashcards work because they combine retrieval practice and spacing, the two techniques rated "high utility" in the largest review of study methods, but common student habits such as small stacks and dropping known cards weaken the effect.

Of 10 study techniques reviewed, only 2 received a high utility rating: practice testing and distributed practice. Flashcards are the most common way students do both (Dunlosky et al., 2013).
Across three experiments with GRE-type word pairs, studying one large stack of flashcards beat studying four smaller stacks separately, and spacing beat cramming on the day before the test. Spacing was more effective for 90% of participants, yet 72% thought the small stacks had worked better after the first session (Kornell, 2009).
When students could drop flashcards they felt they knew, final recall fell to 59%, compared with 63% when they had to keep every card in the deck (Kornell and Bjork, 2007, summarizing Kornell and Bjork, 2008). Across four experiments the effect of dropping was "small but consistently negative".
58% of dropped cards were set aside after a single correct recall, and 20% were dropped without ever being recalled (Kornell and Bjork, 2007).
In a flashcard-style task, learners judged that seeing the full word pair again produced more learning than testing themselves, even though testing was the better mode. They still chose testing most often, mainly to diagnose what they knew (Kornell and Son, 2009).
Students who used flashcards for all three exams in an introductory psychology course scored significantly higher overall than students who used them for none, one or two exams (Golding, Wasarhaley and Fletcher, 2012). This was self-reported and correlational, so stronger students may simply be more likely to make flashcards.
Teaching students a "Flashcards-Plus" method, where cards test comprehension and application as well as definitions, raised exam scores in three studies (n = 73, 62 and 434). In the largest, six introductory psychology courses were randomly assigned, and the three that got the lecture outscored the three that did not (Senzaki et al., 2017).
Among 324 undergraduates, self-testing was positively associated with GPA, and low performers were more likely to study late at night and be driven by deadlines (Hartwig and Dunlosky, 2012).

Myth check: "Drop the cards you already know"

Setting aside cards you got right feels efficient, and 64% of 472 surveyed students said they would do it. The experiments say it costs recall: 59% versus 63% when every card stayed in (Kornell and Bjork, 2007). Getting a card right once shows you know it now, not that you will know it next week. Let the scheduler retire cards instead of your gut.

Key flashcard studies at a glance
Study	Sample	Design	Main finding
Kornell and Bjork (2007, 2008)	472 surveyed, plus lab participants	Survey and experiments	Dropping known cards: 59% recall vs 63%
Kornell (2009)	3 experiments	Experiment	One large stack beat small stacks for 90% of learners
Karpicke et al. (2009)	177 students	Survey	40.1% use flashcards, 6.2% as top strategy
Golding et al. (2012)	415 students	Self-report, correlational	Almost 70% used flashcards; consistent users scored higher
Wissman et al. (2012)	374 students	Survey	Students rarely space their flashcard practice
Senzaki et al. (2017)	73, 62 and 434 students	Classroom studies, one with course-level random assignment	Comprehension-focused flashcards raised exam scores
Deng et al. (2015)	72 medical students	Survey plus exam scores	1,700 unique Anki cards per extra Step 1 point

For how to put these findings into practice, see 7 effective flashcard techniques. The wider evidence on self-testing is collected on our active recall statistics page.

Flashcards in medical school

Medical students are the heaviest Anki users, and the studies that exist link more Anki use to higher Step 1 scores, though almost all of them are observational.

Of 72 students at Washington University School of Medicine, 31% used Anki and 49% used the commercial Firecracker flashcards. Each additional 1,700 unique Anki cards, or 445 practice questions, was associated with one more Step 1 point after controlling for MCAT, grades and test anxiety. Firecracker cards did not predict scores (Deng, Gluckstein and Larsen, 2015).
About 70% of 60 first-year students at the University of Central Florida used Anki in an anatomy and physiology module, with use rising over the 12 weeks (Harris and Chiang, 2022).
A 2026 systematic review of 11 studies found high-frequency Anki users outscored minimal users on Step 1 by 4 to 13 points. Results for in-course exams were mixed, and the one study of Step 2 CK found no significant benefit (Frappa et al., 2026).
At the University of North Carolina, Anki use was associated with higher Step 1 scores, and more consistent users scored higher still (Lu, Farhat and Beck Dallaghan, 2021).

Survey data, pass rates and deck sizes are covered in depth on our medical student Anki statistics page.

Our own data: 18,217 flashcard reviews

In our own logs, accuracy on a card climbs from 69.0% to 97.7% over four attempts, and large decks are rarely finished in one session.

We analyzed 18,217 graded flashcard reviews from 667 students on StudyCards AI, covering 15,104 unique cards, logged between September 21, 2025 and July 28, 2026. The full write-up, including how we cleaned the data, is in We Analyzed 18,000 Flashcard Reviews.

Accuracy on the same card rose from 69.0% on the first attempt to 97.7% on the fourth. Sample sizes shrink with each attempt.

First-attempt accuracy was 69.0% (n = 15,104), rising to 80.5% on the second attempt (n = 2,228), 89.7% on the third (n = 505) and 97.7% on the fourth (n = 215).
Cards students rated "easy" were answered correctly 95.1% of the time (n = 429), "medium" 72.3% (n = 16,456) and "hard" 47.4% (n = 365). The app records "medium" unless the student picks another rating, and correctness is also self-graded, so only the 794 deliberate easy or hard ratings are a real signal.
Median response time was 5.7 seconds for "easy" cards, 4.5 seconds for "medium" and 8.9 seconds for "hard", so hard cards took almost twice as long as easy ones.
Across 1,593 study sessions, completion fell from 25.0% for decks of 1 to 10 cards to 7.8% for decks of 50 or more.

Session completion rate falls as deck size grows. Note the small sample (12 sessions) for the smallest decks.

What this data can and cannot tell you:

It is usage data from one app, not a controlled experiment. It shows correlation, not causation.
The rising accuracy curve partly reflects who keeps going: students who come back to a card a fourth time are not a random sample of those who saw it once.
The 1 to 10 card bucket has only 12 sessions, so the 25.0% figure is noisy. The trend from 11 to 20 cards (n = 52) down to 50+ (n = 1,079) is the sturdier part.
We looked for a relationship between the gap between reviews and recall and could not find a signal clean enough to publish.

Small decks or big stacks?

Our completion data and Kornell (2009) seem to point in opposite directions, but they measure different things. Kornell measured learning: one large stack spaces each card further apart, which helps memory. We measured whether a session was finished. The practical reading is to keep the full set of cards in rotation, so spacing does its work, but study it in sessions short enough that you actually complete them. A spaced repetition scheduler does both at once.

If you want decks built from your own lecture slides or notes, StudyCards AI turns a PDF into flashcards you can study with spaced repetition or export to Anki.

Methodology

We used primary sources only. Usage numbers come from the official Google Play and Apple App Store listings, Quizlet's own press releases, Anki's manual and the relevant GitHub repositories, all read on September 28, 2026. App store figures change daily, and Google Play reports downloads in ranges, so treat them as snapshots. Research findings come from peer-reviewed papers, checked against the publisher, DOI or PubMed record; where only an abstract was accessible, we report only what the abstract states. We did not use statistics roundup sites or Wikipedia as a source for any number. Our own figures come from aggregate, anonymized StudyCards AI review logs.

Sources

AnkiDroid Open Source Team. AnkiDroid Flashcards. Google Play. Accessed September 28, 2026.
Quizlet Inc. Quizlet: More than Flashcards. Google Play. Accessed September 28, 2026.
Quizlet Inc. Quizlet: More than Flashcards. Apple App Store (US). Accessed September 28, 2026.
Ankitects Pty Ltd. AnkiMobile Flashcards. Apple App Store (US). Accessed September 28, 2026.
Quizlet (2025, July 16). Quizlet's How America Learns report explores the future of education through the lens of AI, digital learning, and student success. PR Newswire.
Quizlet (2026, August 4). Quizlet launches new study tools built for the way students learn. PR Newswire.
Ankitects. anki and AnkiDroid contributors, Anki-Android. GitHub. Accessed September 28, 2026.
Open Spaced Repetition. SRS Benchmark. GitHub. Accessed September 28, 2026.
Anki Manual. Deck Options. Accessed September 28, 2026.
Kornell, N. (2009). Optimising learning using flashcards: Spacing is more effective than cramming. Applied Cognitive Psychology, 23(9), 1297 to 1317.
Karpicke, J. D., Butler, A. C., and Roediger, H. L. (2009). Metacognitive strategies in student learning: Do students practise retrieval when they study on their own? Memory, 17(4), 471 to 479.
Kornell, N., and Bjork, R. A. (2007). The promise and perils of self-regulated study. Psychonomic Bulletin and Review, 14(2), 219 to 224.
Kornell, N., and Bjork, R. A. (2008). Optimising self-regulated study: The benefits and costs of dropping flashcards. Memory, 16(2), 125 to 136.
Kornell, N., and Son, L. K. (2009). Learners' choices and beliefs about self-testing. Memory, 17(5), 493 to 501.
Wissman, K. T., Rawson, K. A., and Pyc, M. A. (2012). How and when do students use flashcards? Memory, 20(6), 568 to 579.
Golding, J. M., Wasarhaley, N. E., and Fletcher, B. (2012). The use of flashcards in an introduction to psychology class. Teaching of Psychology, 39(3), 199 to 202.
Senzaki, S., Hackathorn, J., Appleby, D. C., and Gurung, R. A. R. (2017). Reinventing flashcards to increase student learning. Psychology Learning and Teaching, 16(3), 353 to 368.
Hartwig, M. K., and Dunlosky, J. (2012). Study strategies of college students: Are self-testing and scheduling related to achievement? Psychonomic Bulletin and Review, 19(1), 126 to 134.
Dunlosky, J., Rawson, K. A., Marsh, E. J., Nathan, M. J., and Willingham, D. T. (2013). Improving students' learning with effective learning techniques. Psychological Science in the Public Interest, 14(1), 4 to 58.
Deng, F., Gluckstein, J. A., and Larsen, D. P. (2015). Student-directed retrieval practice is a predictor of medical licensing examination performance. Perspectives on Medical Education, 4(6), 308 to 313.
Lu, M., Farhat, J. H., and Beck Dallaghan, G. L. (2021). Enhanced learning and retention of medical knowledge using the mobile flash card application Anki. Medical Science Educator, 31(6), 1975 to 1981.
Harris, D. M., and Chiang, M. (2022). An analysis of Anki usage and strategy of first-year medical students in a structure and function course. Cureus, 14(3), e23530.
Frappa, N., Chernov, D., Dillon, M., and Alben, M. G. (2026). Anki use and academic performance in medical education: A systematic review of evidence and learning theory. Medical Science Educator, 36(2), 1015 to 1025.
Groves, C. (2026). We analyzed 18,000 flashcard reviews: What actually helps you learn. StudyCards AI.

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Frequently Asked Questions

How many people use Anki?

Anki does not publish a user count. The closest official figure is the Google Play listing for AnkiDroid, the free Android app, which showed 10M+ downloads when we checked on September 28, 2026. That is a cumulative install band, not active users, and it excludes the desktop app and the paid iPhone app, AnkiMobile.

How many people use Quizlet?

Quizlet says more than 60 million students, teachers and everyday people use it, a figure repeated in its July 2025 and August 2026 press releases. It also claims 2 in 3 US high school students and 1 in 2 US college students use it. Quizlet does not say whether the 60 million is monthly, yearly or all-time.

Do flashcards actually work, according to research?

Yes, when they are used for retrieval and spaced out. In Kornell (2009), studying one large stack of flashcards beat studying four small stacks for 90% of participants. Golding and colleagues (2012) found that the psychology students who used flashcards for all three exams scored higher than those who did not, though that study was correlational.

What percentage of students use flashcards?

Between about 40% and 70%, depending on the survey. Karpicke, Butler and Roediger (2009) found 40.1% of 177 college students listed flashcards as a study strategy, while Golding, Wasarhaley and Fletcher (2012) found almost 70% of 415 introductory psychology students used flashcards for at least one exam.

How many flashcards should you review per day?

The Anki manual says that learning 20 new cards a day, which is the default, leads to roughly 200 reviews a day once the backlog builds. Its default desired retention is 90%, and it warns that above 97% the workload can be overwhelming. Fewer new cards a day is the main lever for cutting reviews.