How does the completion forecast predict when you will finish a word list?

Tomaru includes a completion forecast tool that simulates your daily study progress day by day to predict when you will finish a vocabulary list. By incorporating your personal review rating history into the FSRS-6 algorithm, the simulator projects your finish date, expected daily review volume, and memory retention curve across iOS, Android, and the web.

What problem does the completion forecast solve?

Spaced repetition algorithms process memory step by step, calculating a card's next review interval only after you rate it. Because the scheduler steps forward one interval at a time, it cannot tell you when you will finish a 1,000-word deck or how many reviews you will face six weeks from now.

Simple arithmetic—such as dividing total list words by a daily new-word target—fails to provide an accurate timeline. Simple division ignores the compounding review load created by every new card introduced into a spaced repetition schedule.

For learners studying toward fixed deadlines like TOEFL, TOEIC, or TOPIK exams, the completion forecast accounts for memory decay and review accumulation to show whether your current study pace matches your target date.

How does the completion simulator work?

Rather than applying a static formula, Tomaru runs a forward day-by-day simulation of your study schedule. On each simulated day, the engine performs four steps:

1. Identifies all cards scheduled to become due on that day.
2. Applies your daily new-word limit and session constraints.
3. Advances the FSRS-6 memory model based on predicted recall outcomes.
4. Records the total required review load and resulting stability scores for that day.

The simulation repeats this sequence until every unlearned card in the word list reaches learned status.

How does Tomaru model your future recall performance?

The completion forecast does not assume perfect performance. Instead, the simulator draws directly from your historical distribution across the four rating buttons (Forgot, Fuzzy, Clear, Know it).

If your review history shows frequent lapses on Forgot or Fuzzy, the simulator factors those failure rates into future reviews, projecting higher review volumes and a later finish date. Conversely, a history of consistent Clear or Know it ratings yields shorter forecasted timelines.

What outputs does the completion forecast provide?

When you run a forecast on a word list, Tomaru generates three specific planning metrics:

How does backward scheduling work?

The forecast tool also operates in reverse. Instead of setting a daily new-word limit and discovering your finish date, you can input a fixed target completion date—such as an upcoming exam date.

The simulator works backward from your chosen deadline, modeling review accumulation and memory decay to calculate the exact daily new-word limit required to finish the list on time.

How should you interpret forecast results?

The completion forecast is a dynamic projection based on current study behavior, not a guaranteed promise. If your daily review consistency, answering speed, or rating accuracy shifts, your projected completion date and daily review loads will shift accordingly.

The main value of the forecast is early detection: it reveals upcoming review spikes weeks before you reach them and highlights unrealistic study plans in week one rather than week six.

To learn how to manage daily queues when time is short, read our guide on Smart Study for limited time or learn how to configure your account settings in daily load and limits.

Related questions

Why does my projected finish date change over time?

Your finish date updates as your study behavior changes. The simulator uses your actual review rating history, so changes in your accuracy or review consistency will recalculate the projection.

Does setting a target completion date automatically change my daily new-word limit?

Setting a target completion date calculates the required daily new-word limit needed to hit that deadline, allowing you to apply that limit directly to your study plan.

Can I run a completion forecast on custom word lists?

Yes. Completion forecasts run on both ready-made public lists and custom lists created through text paste, photo OCR, system selection, or manual entry.