Hermann Ebbinghaus discovered in 1885 that memory decays on a predictable curve — most forgetting happens in the first 24 to 48 hours. The good news: each review flattens the curve, so you remember more for longer with the same total effort.
Move the slider to see where you sit on the curve right now, and get a recommendation for when to review.
Your memory right now
How to beat the forgetting curve
Review within 24 hours
The first review, right before you'd forget, resets the curve and buys you days of retention.
Stretch the interval each time
1 day, then 3, 7, 14, 30. Each successful review flattens the curve further.
Test yourself, don't re-read
Active recall — retrieving the answer from memory — strengthens the trace far more than passive review.
Frequently asked questions
How much do you forget after 24 hours?
With one exposure, most people lose 50–70% of new information within 24 hours. A single well-timed review cuts that loss dramatically.
What is the Ebbinghaus forgetting curve formula?
R = e^(-t/S) — retention R falls as time t grows, and memory strength S controls how fast. More reviews = higher S = slower forgetting.
How many reviews do I need to remember long-term?
Three to five spaced reviews typically lock a memory in for months. After about four reviews, retention often stays above 80% long-term.
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