Best Spaced Repetition Apps for iPhone in 2026

Spaced repetition is one of the most robust findings in memory research: reviewing material at gradually increasing intervals produces far better long-term retention than massed study. Most students know this in theory. The gap is in the tool.

A spaced repetition app is only as good as its scheduling algorithm and how easily you can get your material into it. The best algorithm in the world is useless if building a deck takes three times longer than just making paper flashcards.

This comparison looks at the top spaced repetition apps on iPhone by algorithm quality, creation speed, and practical fit for different study situations.

The Two Algorithms That Matter: SM-2 and FSRS

Most spaced repetition apps in 2026 use one of two core algorithms:

SM-2 (developed by Piotr Wozniak in the 1980s) is the algorithm behind Anki. It calculates the interval between reviews based on a card's "ease factor," which changes based on how well you recall it. SM-2 has an enormous body of real-world validation and works very well across a wide range of subjects.

FSRS (Free Spaced Repetition Scheduler) is a newer algorithm developed with machine learning techniques. In head-to-head comparisons, FSRS shows better retention predictions than SM-2 -- meaning it is more accurate about when you are about to forget something, which translates to more efficient scheduling. It has been integrated into Anki as an optional scheduler since 2023.

The practical difference for most students: FSRS will schedule cards slightly more efficiently, leading to fewer wasted reviews. For a small deck studied over a few weeks, the difference is marginal. For a large deck studied over months, it compounds.

App Comparison

Anki (AnkiMobile)

Algorithm: SM-2 by default; FSRS available as a setting

Creation speed: Slow

Offline: Full

Cost: Free desktop, one-time iOS purchase

Anki is the most powerful spaced repetition tool available. The algorithm is proven, the community is enormous (thousands of shared decks for medicine, law, languages), and the customisation is essentially unlimited.

The weakness is the creation experience. Anki was designed for desktop and the iPhone app reflects that -- it is primarily a review tool, not a creation tool. Making cards on a phone means working around a desktop-first interface.

For students with high-volume, high-stakes material (medical school, bar exam, language fluency), Anki is still the benchmark. For students who want to quickly turn this week's lecture notes into a review deck on their phone, it is not the fastest path.

Quizlet

Algorithm: Proprietary, spaced repetition in "Learn" mode

Creation speed: Fast

Offline: Partial (paid)

Cost: Free with limits; paid plans for full features

Quizlet is the most familiar name in student flashcards. Its "Learn" mode uses spaced repetition principles, though the algorithm is less transparent and less customisable than Anki or FSRS-based tools. For casual study -- vocabulary, basic definitions -- it works well.

The creation experience on iPhone is fast and clean. The large library of shared sets means you often do not have to create anything.

The free tier has tightened significantly. Offline access, AI features, and some study modes now require a subscription.

SimpleQuizMaker

Algorithm: FSRS

Creation speed: Very fast (AI generation)

Offline: Yes (after sync)

Cost: Free (5 AI gen/month); Student plan 150/month; Teacher plan 600/month

SimpleQuizMaker uses FSRS for its flashcard system, which means the scheduling is current-generation -- not a decade-old algorithm, and not a proprietary black box.

The differentiator is how fast you can create a deck. Type a topic or paste your notes, and the AI generates a full set of cards in seconds. For a student who finishes a lecture and wants to start reviewing before the bus journey home, this is the fastest path from notes to spaced repetition practice available on iPhone.

The SimpleQuizMaker app for iPhone supports offline review once decks are synced -- essential for commutes and travel.

The integration with quiz sharing is also worth noting: the same content you study as flashcards can be published as a shareable quiz for classmates or students, without duplicating work.

Brainscape

Algorithm: Confidence-based repetition

Creation speed: Medium

Offline: Yes (paid)

Cost: Free with limits; paid for offline and full features

Brainscape uses a five-point confidence rating to drive scheduling. The interaction is intuitive and the review flow is fast. The algorithm is simpler than SM-2 or FSRS, which means it is less precise for complex long-term learning but perfectly adequate for shorter-term exam prep.

Memrise

Algorithm: Proprietary, multimedia-focused

Creation speed: Fast for pre-built content

Offline: Partial

Cost: Free with limits

Memrise is best for language learning, where its multimedia approach (native speaker audio, video clips, mnemonic associations) adds real value. As a general spaced repetition tool for academic subjects, it is not as strong.

Head-to-Head Summary

| App | Algorithm | AI Creation | Offline | Best For |

|---|---|---|---|---|

| Anki | SM-2 / FSRS | No | Full | High-volume, long-term mastery |

| Quizlet | Proprietary | Yes (paid) | Partial | Casual study, large shared decks |

| SimpleQuizMaker | FSRS | Yes (5 free/mo) | Yes | Fast creation, modern scheduling |

| Brainscape | Confidence-based | No | Yes (paid) | Simple, intuitive review flow |

| Memrise | Proprietary | No | Partial | Language learning |

Which Should You Choose?

Large, high-stakes material studied over months (medical licensing, bar exam, language fluency): Anki with FSRS enabled. The community and algorithm quality at volume are unmatched.

You want to start reviewing today from this morning's lecture: SimpleQuizMaker. The AI gets you from notes to cards in under two minutes, and FSRS handles the scheduling from there.

You need existing shared decks for a popular subject: Quizlet first, Anki shared decks second.

You want the simplest possible review interaction: Brainscape.

Frequently Asked Questions

Is FSRS better than SM-2 for flashcard apps?

In controlled testing, FSRS shows better retention prediction than SM-2, meaning it is more accurate about when you are about to forget something. For most students, the practical difference is modest. For high-volume long-term learning, FSRS's efficiency gains compound over time.

Can I use spaced repetition for short-term exam prep?

Yes, with a caveat: spaced repetition is most powerful over weeks and months. For an exam two days away, active recall practice (self-testing) still works, but you will not get the full benefit of spacing. Start earlier if you can.

Does SimpleQuizMaker sync between iPhone and web?

Yes. Decks created on the web or in the iPhone app sync to your account and are available on both. Reviews completed on your phone update your schedule on the web and vice versa.