Why You Forget 67% of What You Learn in a Day

In 1885 Hermann Ebbinghaus memorized lists of nonsense syllables and tested himself at intervals, producing what we now call the forgetting curve. His numbers are bleak: roughly 58% of new material is gone after twenty minutes, 67% after a day, and 75% inside a week. A 2015 replication published in PLOS ONE found his figures still hold.

What reverses the curve is not more study time but better timing. Spaced repetition spreads reviews across widening intervals, catching material just as it starts to fade. Active recall — testing yourself rather than rereading — consistently outperforms passive review, even though rereading feels more productive while you are doing it.

Our research team looked at what the evidence actually supports, why the two techniques compound when combined, and how to schedule reviews without building a spreadsheet to manage them.

Read the full research: Spaced Repetition and Active Recall on Speed Learning Research.