How to Choose a Free Vocabulary App: Decks, Spaced Repetition and Free-Tier Limits
A comparison of free vocabulary apps by deck availability, spaced repetition, free-tier limits and who each one suits, covering Duolingo, Quizlet, Anki, exam-focused apps and Tomaru.
How to Choose a Free Vocabulary App: Decks, Spaced Repetition and Free-Tier Limits
Choosing a free vocabulary app is not just about whether the download is free. Three things actually matter: whether there are enough ready-made decks you can start using immediately, whether there is spaced repetition to support long-term retention, and whether the free tier lets you complete the core study loop. Plenty of apps are free to install and then run into ads, locked features, or a shortage of decks. Picking the right tool is what makes long-term retention possible, instead of another app you installed and never opened again.
Free to download does not mean genuinely free to study with
Many apps install for free, and the limits only appear once you actually start learning.
Common patterns include ads in the free tier, a limited number of decks, spaced review behind a paywall, AI card generation or speaking practice requiring a subscription, restricted offline use, or a free tier that is really a trial with the core features locked.
None of that is a criticism — many tools offer a free tier precisely so people can try before deciding. But if you plan to build your vocabulary with this app over the long term, you need to know one thing: can the free tier take you through the whole loop of learn new words → schedule reviews → retain long term, or only part of it?
Three things to check first
1. Are there ready-made decks?
However good an app is, if you have to type in several thousand words yourself, most people will not last a week. A good vocabulary app should provide organised decks covering exam preparation, everyday situations and common vocabulary, so you can start learning straight after downloading rather than spending your first sessions preparing material.
2. Is there spaced repetition?
Learning vocabulary is not about seeing a word as many times as possible; it is about coming back shortly before you forget. Apps without a spaced repetition mechanism are usually quizzes or games — satisfying in the short term, poor for retention. A system with spaced repetition tracks how well you know each card and schedules the next review automatically, moving words gradually into long-term memory.
3. Can the free tier complete the core loop?
Concretely, the free tier should let you learn new words, review old ones, use decks, see example sentences and track progress — without ads interrupting or a paywall appearing partway. If it only covers one or two of those, it is a trial version rather than a genuinely free learning tool.
Comparing the common types of free vocabulary app
| Type | Example | What the free tier does | Common limits | Who it suits |
|---|---|---|---|---|
| Gamified language app | Duolingo | Gamified lessons, daily streaks, beginner on-ramp | Ads, energy limits, subscription tier; decks and review scheduling are not transparent | People building a daily habit who enjoy levelling up |
| Flashcard tool | Quizlet | Create or use study sets, flip cards, matching practice | Advanced features need a subscription; set quality depends on the community | People who already have material and want to organise their own cards |
| Highly configurable spaced repetition | Anki | Free on desktop, highly customisable decks, powerful scheduling | Steep learning curve; you source decks and templates yourself; the iOS app is paid | People willing to invest time in configuration and needing customisation |
| Exam-focused vocabulary apps | Various by market | Part of an exam word bank, practice questions | Full word banks and advanced review often paid; narrow focus on specific exams | People with a specific exam target |
| Vocabulary + spaced repetition | Tomaru | Free decks, FSRS spaced review, no ads | Less deeply customisable than Anki; AI extension practice has quota limits that require an upgrade | People who want free decks and a low-friction start |
Is Duolingo good for vocabulary?
Duolingo is good for building the habit of touching a language every day, and for complete beginners its gamified design makes studying less dry. That is its genuine strength.
But if the goal is to build vocabulary systematically — preparing for TOEIC, IELTS or TOEFL, say — or to use spaced review to track the memory state of each individual word, Duolingo is not the best-fitting tool. Its learning path is fixed, word-level control is limited, and there is no deck-centred review scheduling.
Duolingo also has an ad-supported tier and a Super subscription, so there is a real gap between the free and paid experience.
Is Quizlet good for vocabulary?
Quizlet is built around creating and using study sets. Flipping, matching and fill-in-the-blank are all clear and intuitive. If you already have a word list, textbook vocabulary or material from a teacher, Quizlet is a good way to turn it into cards.
However, Quizlet deck quality depends on what you build yourself or find in the community, and that varies widely. If you want to track the memory state of every word systematically over the long term, the spaced review in the free tier is limited, and some advanced study modes require a subscription.
Is Anki good for vocabulary?
Anki is widely regarded as the most complete spaced repetition tool available. Its scheduling has been validated over many years and the community has produced a large number of free decks. For users willing to invest the setup time, Anki can be customised to almost any study need.
The entry barrier is genuinely high, though. Finding reliable decks, understanding deck options, adjusting default parameters and handling cross-device sync all take time to work through. Add that AnkiMobile on iOS is a paid app, and the total cost of entry is not small for someone just starting out.
Anki is an excellent tool — you just have to understand the tool before you can use it to learn.
Who is Tomaru for?
Tomaru positions itself as: free decks, spaced repetition, no tool setup required.
It provides organised free vocabulary decks covering exam preparation, everyday situations and common vocabulary, and uses the FSRS spaced repetition algorithm to schedule reviews automatically. FSRS is the current generation of open-source spaced repetition algorithm, adjusting review timing dynamically according to how each card actually performs rather than cycling through fixed intervals. The core vocabulary loop is free and ad-free.
Beyond card review, Tomaru also supports AI card generation — turning articles, song lyrics or dialogue into vocabulary cards — and words you have studied can feed into grammar practice, shadowing and bidirectional translation.
Tomaru is not trying to replace Anki customisation, nor Duolingo gamification. It addresses a different problem: people who want spaced repetition for vocabulary but do not want to spend time configuring a tool or assembling decks need an option they can simply start with.
Recommendations by need
- Want to touch the language daily and build a habit: Duolingo
- Already have material and want to turn it into cards: Quizlet
- Need full customisation and willing to configure: Anki
- Have a specific exam target: an exam-focused vocabulary app for your market
- Want free decks plus spaced repetition with no setup: Tomaru
These tools are not mutually exclusive. Some people use Duolingo for the habit and Anki or Tomaru for systematic vocabulary; others organise textbook words in Quizlet and pair it with a spaced repetition tool to track retention. Finding the combination that fits your routine matters more than sticking to a single app.
FAQ
Are free vocabulary apps really free?
It helps to separate several kinds of free: free to download, free decks, free review, free AI features. They are not the same thing. Many apps are free to install while the full word bank, ad removal, AI features or advanced scheduling require a subscription. When choosing, confirm one thing: can the free tier take you through the complete vocabulary loop?
What matters most in a free vocabulary app?
Three things: whether there are enough decks for you to start immediately, whether there is spaced repetition to support long-term retention, and whether the free tier lets you keep using the core features long term. Judging by interface polish or how gamified it feels leads easily to a tool that is fun in the short term and poor for retention.
Is Duolingo good for vocabulary?
Duolingo suits habit building and beginner on-ramps, but it is not designed around large deck libraries and spaced repetition. If the goal is exam preparation or systematic vocabulary building, you will usually want to pair it with a tool focused on decks and review scheduling. Duolingo free tier also carries ads, and the full experience requires a subscription.
Is Anki a free vocabulary app?
Anki is free on desktop and on the web, and it is a powerful spaced repetition tool. But you have to assemble decks, configure options and adjust parameters yourself, which takes time to learn, and AnkiMobile on iOS is a paid app. Anki suits users willing to invest time in customising their own study system.
Is Tomaru a free vocabulary app?
Yes. The core vocabulary loop in Tomaru is free and ad-free, and the official decks are free to use. It uses FSRS spaced repetition to schedule reviews automatically, which suits people who want to start learning straight away rather than assembling decks or studying Anki settings first.
Does a vocabulary app have to have spaced repetition?
If the goal is long-term retention, spaced repetition is critical. Apps without it can still run quizzes and short-term practice, but it is easy to see a word many times and forget it quickly anyway. Spaced repetition places the review shortly before you forget, which is among the most efficient review methods memory research currently supports.