What is Tomaru?

What is Tomaru?

Tomaru is a vocabulary-learning application available on iOS, Android, and the web that syncs your progress across all three platforms. Designed for language learners who need to build and maintain a large vocabulary, Tomaru combines the FSRS (Free Spaced Repetition Scheduler) algorithm with personal parameter training, flexible content capture tools, and ready-made word lists.

The app's interface supports 7 languages: English, Traditional Chinese, Simplified Chinese, Japanese, Korean, Indonesian, and Hindi. Learners can use Tomaru to study 6 target languages: English, Japanese, Korean, French, Spanish, and German. Ready-made lists come with card explanations, grammar notes, and definitions written in the learner's own language, which you select when choosing a list.

All core learning features in Tomaru are completely free. You can create unlimited cards, build unlimited lists, perform unlimited reviews, access full FSRS scheduling, and run personalized algorithm optimizations without a paid plan.

How does Tomaru schedule vocabulary reviews?

Tomaru manages your study schedule using FSRS, an open-source spaced repetition algorithm. FSRS tracks three distinct values for every card in your deck: retrievability (the probability that you can recall the word right now), stability (how slowly that recall probability decays over time), and difficulty (how challenging the word is relative to your overall learning history).

A card appears for review at the precise moment its estimated recall probability drops to your chosen target retention rate. You can set this target retention rate to 85, 90, or 95 percent, with 90 percent set as the default. Selecting a higher retention rate increases the number of repetitions required per word, which reduces the number of new words you can introduce within a given daily study time.

• Retrievability: The probability that you can recall the word right now.
• Stability: How slowly that recall probability decays over time.
• Difficulty: How challenging the word is relative to your overall learning history.

Standard spaced repetition algorithms rely on fixed population averages to guess when you will forget a word. Tomaru customizes this scheduling to your specific memory patterns. Once you complete roughly 1,000 qualifying reviews—counting only reviews spaced at least one day apart for a given card—you can start parameter optimization in your settings. Tomaru fits all 21 FSRS parameters on our servers using the official FSRS optimizer. The finished parameter set is then applied automatically across every device and word list, eliminating the need to calculate or transfer numbers manually.

What content is available in the app?

Tomaru includes a library of ready-made content containing more than 410,000 cards distributed across over 150 public word lists. These lists align with specific language goals and standard proficiency frameworks, including TOEFL, TOEIC, IELTS, GRE, SAT, TOPIK, CEFR levels, business vocabulary, and everyday conversation.

Card audio uses high-quality neural speech models rather than your device's built-in text-to-speech engine. For English vocabulary, Tomaru provides multiple accent and gender options, while Japanese and Korean lists include an additional voice option.

How do you add new words to Tomaru?

In addition to ready-made lists, Tomaru offers seven distinct ways to import or create custom vocabulary cards. Every method processes your input into a complete card that enters your active FSRS schedule:

1. Text paste: Paste articles, song lyrics, or reading passages. Tomaru segments language naturally, reducing conjugated forms like Japanese verbs down to their dictionary base forms.
2. Photo and screenshot OCR: Capture printed text or screens with optical character recognition and select specific regions to import.
3. System text selection: Select text inside other mobile applications. On Android, Tomaru integrates directly into the system text-selection menu; on iOS, it functions as a system translation provider.
4. Sentence translation queries: Ask how to express a specific sentence, and Tomaru builds a card containing the full translation and its structural breakdown.
5. In-session lookup: Search for unfamiliar words during active review sessions and convert them into cards immediately.
6. Manual card creation: Build cards from scratch, including image-occlusion cards with custom masks drawn directly on your phone screen.
7. Public list installation: Add any of the over 150 pre-made lists to your collection.

How does Tomaru optimize study time?

When your review queue exceeds your available study time, Tomaru uses Smart Study to prioritize cards. Smart Study analyzes your historical answering speed, calculates the memory gain per second each due card offers, and selects the highest-value cards to fill your specified time limit.

To help you manage long-term goals, Tomaru provides a completion forecast tool. The app simulates daily progress using your historical rating distribution to project a completion date, daily review loads, and a retention curve. You can also work backward by selecting a target completion date to calculate the required daily new-word limit.

After you learn 50 words, Tomaru can generate custom reading passages composed of words you have reviewed, supplemented by upcoming words from your list to provide contextual practice.

What features are free, and what features have limits?

Tomaru provides all core flashcard operations, algorithm optimizations, widgets, and statistics without charge. Weekly quotas apply only to features that process data through AI models or synthesize audio.

Audio playback counts against your weekly quota regardless of whether the audio clip was previously played or generated. For full details on subscription tiers, visit our pricing page.

Related questions

Can I review words from my phone's home screen?

Yes. Tomaru provides home screen widgets for iOS and Android that include all four rating buttons. Reviews completed through the widget save directly to your main sync record.

How does Tomaru handle conjugated words when pasting text?

Tomaru uses language-specific segmentation tools rather than raw string splitting. For example, conjugated Japanese verbs in pasted passages are automatically converted to their dictionary forms before card creation.

Does Tomaru offer different English accents for audio?

Yes. English audio playback includes multiple accent and gender options generated by high-quality speech models rather than default device text-to-speech engines.

When can I optimize my personal parameters?

You can start parameter optimization in your settings once you accumulate roughly 1,000 reviews on your account. Only reviews logged at least one day after the previous review of that same card count toward this total, excluding same-day repeats. Tomaru fits all 21 FSRS parameters on our servers and applies the finished values automatically across all your devices.