Statistics

Statistics on readfrog.app shows what your reviewing has actually produced. It covers every notebase by default; the Notebase filter narrows it to one, and the range selector offers the last 7 days, 30 days, 3 months, year, or all time.

The numbers at the top

• Reviews — how many times you graded a card in the range. One card reviewed three times counts three.
• Review time — how long you spent, which is often the more honest number: a high review count in very little time usually means you were pressing Good without reading.
• Active days — days with at least one review. For spaced repetition this matters more than volume; the schedule assumes you turn up.

Activity

A heatmap of the last year, one square per day, darker for more activity. Under it, the same range as counts of learned cards and new notes.

The two lines answer different questions. New notes is how much you are collecting — easy to run ahead on, because saving a word takes a second. Learned cards is how much you are actually turning into memory. A heatmap that keeps growing on notes and stays pale on reviews is the usual shape of a stalled deck.

Long-term memory growth

A card counts toward long-term memory once its scheduled interval is long enough that you are no longer relearning it. The chart tracks that count over time, with the daily change beneath.

This is the closest thing to a progress bar that spaced repetition offers. It moves slowly on purpose: a card only joins after surviving several correct recalls at widening intervals, so a burst of reviewing today shows up here weeks later. Reviews you get wrong pull cards back out of it.

Note growth

How many notes exist over time, which is the collection side rather than the memory side. Useful mainly next to the memory chart — the gap between the two lines is your backlog.

One card's forgetting curve

Open a card from its notebase to see its own memory history rather than the aggregate:

• Memory stability — roughly how long this card can go before recall drops to the target. It grows each time you recall the card correctly.
• Retrievability — the estimated chance you would recall it right now. Falls between reviews.
• Lapses — how many times you forgot it after having learned it. A card with many lapses is usually a card that needs rewriting, not more reviews.
• Review history — every grade with its time, duration, and the card's state and stability beforehand.

The chart draws three curves: the forgetting curve after your most recent review, the reference curve for a card with no review history, and your target retention. The distance between the first two is what your reviewing has bought.

Where the numbers come from

Every grade is recorded with its rating and timing, and the scheduler derives stability and the next interval from that history — see How Scheduling Works. Nothing here is an estimate of your language level; it only describes the cards you have reviewed.

Days are bucketed in your own timezone, so a review at 1 a.m. lands on the day you experienced, not UTC's.