"Free" is doing a lot of work in the vocabulary app market.

Some apps are genuinely free and genuinely useful. Some are free in the sense that you can technically use them without paying, if you are willing to watch an advertisement every forty-five seconds and accept that the most useful features are locked behind a paywall that grows more insistent every time you open the app. Some are free in the sense that someone, somewhere, is getting paid by your attention and your data.

Here is an honest breakdown of the best free vocabulary apps in 2026 — what you actually get, what you do not, and when it is worth upgrading.

What "Free" Usually Means

Before the rankings, a quick taxonomy of free.

Genuinely free. No paid tier, no ads, no premium features. The entire product is available at no cost. Rare, but it exists. Anki's desktop version is the main example.

Freemium. A core product is free, with paid features on top. This is the most common model. The question is how useful the free tier actually is versus how aggressively the app pushes you toward payment.

Ad-supported free. The app is free but monetised through advertising. The ads range from tolerable to so intrusive they effectively make the app unusable without paying.

Free trial. Not really free — a limited-time access to the paid product. Worth noting, because many apps describe a 7-day trial as "free."

The Rankings

1. Anki (Desktop) — Genuinely free, genuinely powerful

Anki's desktop app is completely free, open-source, and probably the most powerful spaced repetition system available at any price point. The mobile apps charge a one-time fee (AnkiMobile on iOS is £25; AnkiDroid on Android is free).

What you get for free: full access to the spaced repetition algorithm, the ability to create any type of card, access to a community library of millions of pre-built decks, and the ability to synchronise across devices.

What you do not get: a modern interface, automatic card generation, or anything that reduces the setup overhead. Anki rewards the learner who is willing to invest time in building a good deck. For learners who are not, the free tier of a better-designed app may serve them more effectively.

Best free option for: dedicated learners who want maximum power and are willing to invest in setup.

2. Vokabulo (Free Tier) — AI vocabulary building with no commitment

Vokabulo offers a free trial that gives full access to the core features — including the AI card generation, Scenes Mode, and spaced repetition — with no strings attached.

What this means in practice: you can capture vocabulary from your real life, generate AI-powered context sentences, build vocabulary sets for specific scenarios, and study with adaptive spaced repetition, all without paying anything upfront. The trial is designed to give you a genuine sense of what the app does rather than a frustratingly limited preview.

For learners who are serious about building real-life vocabulary — professionals, expats, intermediate to advanced learners — the free trial is a meaningful opportunity to test whether the approach works before committing.

Best free option for: learners who want to test AI-powered vocabulary building from their real life.

3. Duolingo (Free Tier) — Capable but ad-heavy

Duolingo's free tier is functional. The core learning experience — lessons, exercises, the streak — is available without payment. The catch is the advertising, which has become increasingly aggressive. On the free tier you will see ads between lessons, and the app nudges you toward Duolingo Plus at regular intervals.

For absolute beginners who are not yet sure whether they will stick with language learning, the free tier is a low-risk way to start. For learners past the beginner stage, the ads and the limitations of the free content become friction that the paid tier removes.

What the free tier lacks compared to paid: unlimited hearts (you lose the ability to make mistakes freely), no offline access, and ads throughout.

Best free option for: complete beginners testing the waters.

4. Memrise (Free Tier) — Limited but the listening feature is the point

Memrise's best feature — the native speaker video clips — is available on the free tier, at least in part. The free content covers a reasonable range of vocabulary for major languages and is genuinely useful for ear training.

The free tier becomes restricted fairly quickly on less common languages and at higher levels. If you are learning French, Spanish, or German at a basic level, the free content is decent. Beyond that, you will hit the paywall.

Best free option for: beginners who want to hear how native speakers actually sound.

5. Clozemaster (Free Tier) — Huge sentence database, basic interface

Clozemaster's free tier gives access to a genuinely large database of gap-fill sentences in a wide range of languages. The interface is minimal — some would say charmingly retro, others would say dated — but the exposure to sentences in context is real.

The free tier includes a limited number of sentences per day and no advanced statistics. The paid tier removes these limits and adds features. For intermediate learners who want sentence-level vocabulary exposure, the free tier is worth exploring.

Best free option for: intermediate learners who want volume of sentence exposure.

The Free-to-Paid Question

Every freemium vocabulary app eventually asks you to upgrade. The question is whether the paid tier is worth it.

The honest answer is: it depends what you are trying to achieve.

If you are a casual learner — you study for ten minutes when you remember, you have no urgent need for the language, you are interested but not committed — the free tiers of most apps will serve you adequately. The limitations are real but not critical.

If you are a serious learner — you have a professional or personal reason to actually acquire this language, you are using it regularly, you want vocabulary that transfers to real situations — the free tier limitations will frustrate you. The ads interrupt focus. The feature caps slow progress. The missing features are often exactly the features that matter.

For the serious learner, the investment in a quality paid tool is quickly justified. The vocabulary you are trying to build has real career or life value. The tool you use to build it should not be the cheapest one available — it should be the most effective one available.

Vokabulo's free trial exists precisely for this reason: to give serious learners the chance to experience what the product actually does before making that decision.

Try Vokabulo free — no strings attached. Build vocabulary from your real life and see what AI-powered learning actually feels like.