Search for "best free learning app" and you'll get dozens of lists that disagree. Part of the problem is that "free" means different things. Some apps are free outright. Others are free to start and then lock key features. Some are free because they show ads. Your study material and your habits matter more than any ranking.
What "free" usually means
Most apps on these lists are freemium. You get a usable free tier and pay for extras. Apps that keep the core study modes free tend to get far fewer complaints from students. The most common frustration with flashcard apps is a study mode that was free last year and now sits behind a subscription.
The main options
Anki is the long-standing choice for serious memorization. It's free on desktop and Android. The iOS app costs a one-time fee. Its spaced repetition is strong, but the interface looks dated and takes time to learn.
Quizlet is the most familiar name, with a large library of shared study sets. Many users now feel that the modes that actually make you practice are paywalled through Plus, so the free version is more limited than most people expect.
Knowt is a free alternative for students who like Quizlet-style modes. One comparison says the modes Quizlet gates are free there and uncapped, and that an importer can move existing Quizlet sets over in a few minutes. That source is a study-guide company that also sells its own product, so verify it before you commit.
Khan Academy is the best free option for structured learning across math, science, and the humanities, with no paywall. It's a course platform rather than a flashcard tool, so it works best paired with something else.
Duolingo leads free language learning. Core lessons are free, and a paid tier adds extras. It builds a daily habit well, but it won't get you to fluency alone.
Which one should you pick?
The right choice depends on the job:
Memorizing facts for the long term: Anki, if you can tolerate the interface.
Exam prep with existing sets: Knowt, if you want uncapped free study modes.
Learning a subject from scratch: Khan Academy.
Languages: Duolingo for the habit, then add something with more depth.
Most learning comes from retrieving information and practicing problems, not from rereading notes. Apps that make that easy usually earn their place.
Where topic-learner fits
Most flashcard apps still make you write every card yourself, and for many learners that is the biggest obstacle. topic-learner is an AI-powered study app that turns your documents into quizzes and flashcards. You give it your material and start studying, without spending an evening typing cards from lecture notes or a textbook chapter.
It may suit you if you:
Already have study material as documents and want to skip making cards
Want quizzes and flashcards from the same source, so you can test recall in more than one way
Prefer to spend your time on retrieval practice rather than setup
Check topic-learner's current free tier and limits on its site, because pricing and features may have changed since this was written. Also review the generated questions against your material. AI output is a useful starting point, but a quick check takes little time and catches mistakes.