The Best Spaced Repetition Apps in 2026

Q: What is the best spaced repetition algorithm in 2026?

For most people, FSRS (the Free Spaced Repetition Scheduler) is the state of the art available in general-purpose apps — it is a machine-learning model trained on real review data and is the default in Anki and an option in RemNote and Mochi-style apps. SuperMemo's proprietary SM-18 and SM-19 algorithms are comparably sophisticated and arguably the most precise of all, but they are locked inside SuperMemo. Apps still running only the older SM-2 algorithm are at a real, measurable disadvantage.

Quick Answer: The best spaced repetition app in 2026 depends on what you are trying to remember. For raw scheduling power and a free, no-compromise toolkit, Anki is still the default — it runs the modern FSRS algorithm, costs nothing on desktop, and has the deepest add-on ecosystem. For people who take notes and want cards generated from those notes in one place, RemNote is the best choice. For absolute scheduling precision and nothing else, SuperMemo is unmatched but punishing to use. For students cramming defined curricula, Quizlet and Brainscape are the path of least resistance. For a clean, markdown-native minimalist deck, Mochi wins. For language learning specifically, Memrise is purpose-built. And for readers — people who want to retain the books they actually finish rather than build decks from scratch — Chapterly is the right pick, because it turns your highlights into spaced-repetition cards automatically and ties them to an AI tutor that can quiz you on the source. The rest of this article explains the criteria behind those picks and the honest weaknesses of every option.

Spaced repetition is the most reliably effective memory technique cognitive psychology has produced. The finding — that reviewing material at expanding intervals dramatically outperforms massed study — has held up across more than a century of research, from Ebbinghaus in the 1880s to modern meta-analyses. None of that is in dispute. What is in dispute, every time someone tries to actually adopt the habit, is which app to use. The wrong app does not just slow you down; it quietly kills the habit, because spaced repetition only works if you keep coming back, and you only keep coming back to software that does not annoy you.

This guide compares the eight apps that genuinely matter in 2026. It is not a ranking, because the apps serve different people. It is a criteria-driven breakdown so you can match the tool to your actual use case. If you want the underlying theory first, start with how to use spaced repetition and spaced repetition for readers.

How We Picked These Apps

Every app below was evaluated against five criteria. We weight them in roughly this order because, in practice, this is the order in which they decide whether the habit survives.

Algorithm quality and FSRS support. The scheduling algorithm determines how efficiently the app spaces reviews. The 2026 state of the art is FSRS (the Free Spaced Repetition Scheduler), a machine-learning model trained on real review data that personalizes intervals far better than the older SM-2 algorithm most apps shipped for two decades. SuperMemo's proprietary SM-18 family is comparably sophisticated. An app running plain SM-2 or a vague undisclosed algorithm is at a measurable disadvantage.
Friction to create cards. The single biggest reason spaced repetition fails is not the reviewing — it is the making. If turning something you want to remember into a card takes two minutes of formatting, you will stop. We score how fast a card goes from "thing I read" to "card in a deck."
Mobile experience. Reviews happen in the gaps of a day: a commute, a queue, a waiting room. An app with a weak or expensive mobile client loses most of its review opportunities.
Price — including the parts the marketing page hides. Free tiers are often crippled, and the real cost is sometimes on a platform the headline price does not mention (AnkiMobile is the famous example).
Whether it connects to actual reading. This is the criterion most comparisons skip entirely. A flashcard app is only as useful as the material you put into it — a point we expand on in the roundup of the best AI flashcard apps, which grades each tool by how well it turns real reading into cards. An app that sits next to your books — that ingests highlights, links cards to their source, and lets you revisit the original context — removes the largest chunk of friction for anyone whose goal is remembering what they read rather than memorizing a fixed syllabus.

The Comparison Table

App	Best for	Spaced-repetition algorithm	Price	Data export
Anki	Power users who want maximum control	FSRS (default since 2023), SM-2 fallback	Free on desktop/Android; ~$25 one-time on iOS	Open `.apkg` format, easiest to migrate
RemNote	Note-takers who study from their own notes	FSRS and SM-2	Generous free tier; Pro ~$8/mo	CSV / markdown export
SuperMemo	Precision maximalists, ultra-long-term retention	Proprietary SM-18 / SM-19 family	~$6/mo (web); legacy desktop one-time	Proprietary, hard to migrate
Quizlet	Students with defined curricula and exams	SM-2-style "Learn" mode	Free tier; Plus ~$3/mo	Export cards, loses study history
Brainscape	Exam prep with curated, certified decks	Proprietary confidence-based intervals	Free tier; Pro ~$20/mo	Export cards, loses confidence data
Mochi	Minimalists who write cards in markdown	FSRS-style scheduling	Free tier; Pro ~$5/mo	Native markdown export
Memrise	Language learners specifically	Proprietary, video-immersion focused	Free tier; subscription ~$9/mo	Limited, user decks deprecated
Chapterly	Readers who want to retain books they finish	Spaced repetition tuned for reading recall	Free tier; paid plan	Source highlights exportable

Prices are approximate 2026 figures and vary by region, billing cycle, and promotions. Treat them as orientation, not quotes.

Anki

Who it is for: Anyone willing to invest an afternoon in setup in exchange for the most powerful free spaced-repetition engine available. Medical and law students are the heaviest users, but Anki suits anyone who wants total control.

Strengths. Anki adopted FSRS as its default scheduler in 2023, which means the free app now runs a genuinely state-of-the-art algorithm. It is endlessly extensible through a massive add-on library, supports any card type you can imagine, syncs across every platform, and stores your data in an open format you fully own. There is no funnel toward a paywall on desktop.

Real weaknesses. The interface looks like a tool from 2008 because, structurally, it is. The learning curve is steep — card templates, note types, and add-on configuration are genuinely confusing for newcomers. Card creation is slow unless you build muscle memory or import decks. And Anki does nothing to help you decide what to make cards from; it assumes you arrive with material in hand.

Pricing reality. Free on desktop, free on Android (AnkiDroid), free on the web sync. The catch is iOS: AnkiMobile is a one-time purchase of roughly $25. It is not a subscription and the money funds the project, but iPhone users should know the "free" reputation has an asterisk.

RemNote

Who it is for: People who already take structured notes and want their flashcards to live inside those notes rather than in a separate app.

Strengths. RemNote's defining feature is that it collapses the gap between note-taking and studying. You write notes as outlines, and a keyboard shortcut turns any line into a flashcard that stays linked to its surrounding context. It supports both SM-2 and FSRS scheduling, so the algorithm is current. For students who study from their own course notes, this single-environment workflow removes a real source of friction.

Real weaknesses. RemNote tries to be a note app and a flashcard app and a knowledge base, and the breadth shows: it can feel heavy and occasionally slow, and the feature surface is large enough to be intimidating. If you do not want a full notes system, you are carrying weight you will not use.

Pricing reality. The free tier is genuinely generous and sufficient for many students. Pro (around $8/month) unlocks unlimited uploads, advanced PDF tools, and offline access. Reasonable, but you are paying for the notes platform as much as the spaced repetition.

SuperMemo

Who it is for: Retention maximalists who care more about scheduling precision than about anything else, and who can tolerate a difficult interface.

Strengths. SuperMemo is where spaced repetition was invented, and its proprietary algorithm — the SM-18 and SM-19 family — remains the most sophisticated scheduling engine in existence, modeling item difficulty and memory stability in ways FSRS only recently approached. Its incremental-reading feature, which interleaves reading and review, is unique and genuinely powerful for processing large volumes of text.

Real weaknesses. The interface is the most punishing in this comparison — dense, idiosyncratic, and unwelcoming. The mobile and web versions have historically lagged the Windows desktop app in capability. The learning curve is steeper than Anki's, and that is a high bar.

Pricing reality. The web version runs around $6/month. The legacy Windows desktop apps have one-time-purchase versions. You pay, in money and in patience, for the best algorithm.

Quizlet

Who it is for: Students working through a defined curriculum — vocabulary lists, exam terms, course glossaries — who want the lowest possible barrier to entry.

Strengths. Quizlet is the most frictionless app here to start with. Making a set takes minutes, the interface is friendly, and there is an enormous library of user-created sets, so for popular courses someone has often already built your deck. Games and varied study modes keep casual learners engaged.

Real weaknesses. Quizlet is not a true spaced-repetition app in the rigorous sense. Its "Learn" mode does adaptive review, but the scheduling is far less precise than FSRS or SM-18, and it is not designed for long-term retention of large card collections over months and years. It is built for the next exam, not for permanent knowledge. Recent changes have also moved features that were once free behind the Plus paywall.

Pricing reality. A free tier exists but has been steadily narrowed — practice tests, Learn rounds, and other features are now metered. Quizlet Plus runs around $3/month billed annually.

Brainscape

Who it is for: Test-takers who want professionally made, certified decks for standardized exams and prefer curated content over building their own.

Strengths. Brainscape's strongest asset is its curated content: high-quality, expert-verified decks for major exams. Its confidence-based repetition asks you to rate how well you knew each card, and schedules accordingly. The interface is clean and modern, and the mobile apps are solid.

Real weaknesses. The scheduling algorithm is proprietary and simpler than FSRS — it leans on your self-reported confidence rather than a trained model of memory decay. It is best suited to its curated decks; as a general-purpose tool for your own material it is less flexible than Anki or RemNote.

Pricing reality. There is a free tier, but Brainscape Pro is the most expensive option in this comparison at roughly $20/month. The price is aimed at exam candidates for whom a curated, certified deck is worth real money.

Mochi

Who it is for: Minimalists who want a clean, fast, markdown-native card app with no clutter.

Strengths. Mochi is the antidote to feature bloat. Cards are written in markdown, the interface is calm and uncluttered, and the scheduling is modern and FSRS-style. It supports two-sided cards, cloze deletions, and templates without burying them under options. If Anki feels like too much machinery and Quizlet feels too shallow, Mochi sits in the gap.

Real weaknesses. The ecosystem is small — far fewer shared decks, integrations, and add-ons than Anki. There is no first-party native mobile app on the level of the desktop client, which weakens the review-in-the-gaps use case. It is a focused tool, and focus means fewer escape hatches.

Pricing reality. A usable free tier with a card limit; Pro is around $5/month for unlimited cards and sync. Honest and affordable.

Memrise

Who it is for: Language learners specifically — and almost no one else.

Strengths. Memrise has narrowed its focus to language acquisition, and within that lane it is strong. It pairs spaced repetition with video clips of native speakers using words in context, which builds listening comprehension alongside vocabulary. For learning words and phrases in a new language, the immersion approach works well.

Real weaknesses. Memrise is no longer a good general-purpose spaced-repetition app. User-created course tools have been deprioritized in favor of the company's own language content. If you want to remember anything other than a language — concepts from a book, facts for an exam, professional knowledge — Memrise is the wrong tool.

Pricing reality. A limited free tier; full access runs around $9/month or is discounted heavily on annual and lifetime plans. You are paying for language content, not for a flexible card engine.

Chapterly

Who it is for: Readers. People whose goal is not to memorize a fixed syllabus but to actually retain the nonfiction books they finish — and who do not want to spend their evenings hand-building decks.

Strengths. Chapterly starts from a different premise than every other app on this list. Anki, RemNote, SuperMemo, and the rest assume you arrive with material already in hand; the hardest part of using them is deciding what to make cards from and then making them. Chapterly removes that step for readers: it takes the highlights and notes from books you read, turns them into spaced-repetition cards automatically, and schedules them for review. Each card stays tied to its source, so you can always jump back to the passage it came from. On top of the review system sits an AI tutor that can quiz you on a book, push back on your interpretation, and connect ideas across everything you have read — which means review is an actual conversation about the book rather than a flip-the-card drill. For the recall-vs-recognition problem that defeats most readers, that combination is the point.

Real weaknesses. Chapterly is not a general-purpose flashcard tool, and it does not pretend to be. If you need to memorize anatomy diagrams, legal statutes, or a Spanish vocabulary list, Anki or a dedicated language app will serve you better. Chapterly is deliberately specialized for reading retention. It is also web-first rather than shipping heavy native desktop clients.

Pricing reality. There is a free tier you can use without a card limit penalty, and a paid plan for heavier use. The honest framing: if you read books and want to remember them, Chapterly does the part the other apps make you do by hand.

What Is the Best Free Spaced Repetition App?

For an unrestricted, no-compromise free experience, Anki is the answer — on desktop and Android it is fully free, runs the FSRS algorithm, and has no feature paywall. The only asterisk is the one-time iOS purchase. RemNote and Mochi also have genuinely usable free tiers if you want a more modern interface and can live within their limits. Quizlet's free tier has narrowed enough that it is no longer the easy free recommendation it once was. If your goal is specifically remembering books, Chapterly's free tier is built around that use case rather than around metering you toward an upgrade.

Is Anki Still Worth It in 2026?

Yes — with one honest caveat. Anki adopting FSRS as its default scheduler closed the one real gap between it and newer apps: it is no longer "powerful but algorithmically dated." In 2026 it is powerful and current, and still free. The caveat is unchanged: the interface and the setup curve are genuinely off-putting, and Anki does nothing to help you decide what to study. If you are disciplined, technical, and arrive with material in hand, Anki is still the best value in the category. If the setup friction is what has stopped you before, a more guided tool — one that generates cards from your reading instead of making you build them — will get you further, because the best algorithm in the world does nothing if the app stays closed.

Do I Need a Spaced Repetition App if I Just Want to Remember Books?

You need spaced repetition — the technique. Whether you need a general-purpose flashcard app is a separate question, and for most readers the answer is no. General-purpose apps like Anki are built for memorizing defined material: vocabulary, formulas, exam facts. Books are not defined material. The hard parts of remembering a book are deciding which ideas are worth keeping, phrasing them as good prompts, and connecting them to other books — and a blank Anki deck helps with none of that.

What readers actually need is a tool that sits next to the reading itself: one that captures highlights, converts them into review prompts without manual formatting, keeps each prompt linked to its source passage, and ideally lets you discuss the ideas rather than just flip cards. That is the gap Chapterly is built for. If you want to understand the technique before choosing any tool, spaced repetition for readers and how to create flashcards from books cover the method in depth, and how to remember what you read explains why passive re-reading fails in the first place.

How to Choose Between These Apps

Match the tool to the job:

You want maximum power and control, and you are technical: Anki.
You study from your own structured notes: RemNote.
You want the best possible algorithm and can tolerate a hard interface: SuperMemo.
You are cramming a defined curriculum for an exam soon: Quizlet or Brainscape.
You want a clean, minimal markdown card app: Mochi.
You are learning a language: Memrise (or Anki with a language deck).
You want to retain the nonfiction books you read without building decks by hand: Chapterly.

The most common mistake is choosing the most powerful app rather than the one that fits your actual goal. Power you will not use is friction, and friction is what kills the spaced-repetition habit. For a broader look at tools beyond pure flashcards, see the best reading retention apps.

Frequently Asked Questions

What is the best spaced repetition algorithm in 2026?

For most people, FSRS (the Free Spaced Repetition Scheduler) is the state of the art available in general-purpose apps — it is a machine-learning model trained on real review data and is the default in Anki and an option in RemNote and Mochi-style apps. SuperMemo's proprietary SM-18 and SM-19 algorithms are comparably sophisticated and arguably the most precise of all, but they are locked inside SuperMemo. Apps still running only the older SM-2 algorithm are at a real, measurable disadvantage.

Is Anki or Quizlet better for spaced repetition?

For genuine long-term retention, Anki is better — it runs FSRS, is built for permanent knowledge, and handles large card collections over years. Quizlet is faster and friendlier to start with and is fine for the next exam, but its scheduling is less precise and it is not designed for years-long retention. Choose Anki for durable knowledge, Quizlet for short-term cramming.

What is the best spaced repetition app for remembering books?

A general-purpose flashcard app is a poor fit for books because the hardest part — deciding what to keep and phrasing it as a prompt — is left entirely to you. Chapterly is built specifically for this case: it converts your highlights into spaced-repetition cards automatically, links each card to its source passage, and adds an AI tutor that can quiz you on the book. For memorizing fixed material like vocabulary or formulas, Anki remains the stronger choice.

Do I have to make my own flashcards?

With most apps on this list, yes — and that manual card-making is the most common reason people quit spaced repetition. Some apps reduce it: Quizlet and Brainscape offer large libraries of pre-made decks, and RemNote generates cards from notes you are already writing. Chapterly removes the step entirely for readers by generating cards from the highlights you make while reading.

Is spaced repetition worth it?

Yes. The expanding-interval review effect is one of the most robust findings in cognitive psychology, replicated for well over a century. The real question is never whether the technique works — it is whether you will keep using the app. That is why fit matters more than raw power: the best app for you is the one whose card-making friction is low enough that you actually come back. See how to use spaced repetition for the practical method.

The Economics of Spaced Repetition: Why Card Creation Matters More Than Algorithm

Almost every spaced-repetition comparison focuses on algorithm quality — FSRS vs SM-2 vs proprietary scheduling — and almost every comparison gets the practical importance backwards. Algorithm differences matter at the margin; card-creation friction matters at the foundation. Here is the math.

Suppose you read 30 books a year and want to retain the most important 10 ideas from each. That is 300 cards a year, or roughly one every 36 hours. If creating each card takes 5 minutes of formatting, prompt writing, and tagging — typical for Anki with reasonable card design — you are spending 25 hours a year on card creation alone before you do a single review. If you switch to an app that reduces card creation to 30 seconds (because it generates the prompts from your existing highlights), you reclaim 22.5 hours per year. That is enough time to read four additional books — books which will themselves produce more cards, compounding the gain.

The algorithm question, meanwhile, asks something like: does FSRS save you 15-20% of review time compared with SM-2 once your deck is mature? Yes, it probably does. But that gain is on review time, which for a 300-card-a-year reader might be 30 hours annually. A 15% improvement saves 4-5 hours. Against the 22.5 hours of card creation the better-card-creation app saved, the algorithm advantage is roughly a fifth as large.

The implication for the apps in this guide is direct. Anki has the best free algorithm and the worst card-creation friction for readers. Chapterly has good-enough scheduling and the lowest card-creation friction for readers, because the cards come from highlights you were already making. RemNote splits the difference. The right app for any individual reader depends on whether they are bottlenecked on review efficiency or on getting cards into the system in the first place — and for most serious readers, it is the second. For more on how this fits into the broader how to remember what you read workflow, see also how to create flashcards from books.

Data Portability: What Happens If You Switch Apps Later

Almost no comparison of these apps mentions the question that matters most once you have a year of reviews invested: can you get your cards back out? This is worth answering before you commit, not after you are 2,000 cards deep and stuck.

Anki is the gold standard here — its .apkg format is open, widely supported, and importable into most competitors, which is a real reason its steep learning curve is worth tolerating for long-term collections. RemNote and Mochi both support standard export formats (CSV, markdown), so switching later costs you formatting time but not your content. SuperMemo and Memrise are the two worst offenders: SuperMemo's proprietary collection format is difficult to migrate cleanly, and Memrise's user-created course data has been deprecated in ways that made some learners' decks effectively unrecoverable. Quizlet and Brainscape allow export but strip some of the app-specific study metadata (confidence ratings, review history) in the process — you keep the cards, not the learning curve you built.

For Chapterly, the honest answer is that portability matters less because the premise is different: the cards are generated from highlights tied to books you have read, and the highlights themselves — not just the derived flashcards — are what you actually own and can export. If you stop using Chapterly, you keep the source material the cards were built from, which is a stronger guarantee than most flashcard-first apps offer for their raw card data.

The practical rule: if you are building a multi-year deck from scratch (a language, a licensing exam, a body of professional knowledge), weight portability heavily and lean toward Anki. If your cards are a byproduct of reading you would be doing anyway, portability of the source material matters more than portability of the derived cards.