Forgetting Curve Simulator
Memory fades on a predictable curve. Add a few well-timed reviews and watch it hold. Drag your own schedule together and see the difference.
With this schedule you hold roughly 62% after 60 days, versus 0% from a single study session. Average retention across the whole period: 80%.
Try a schedule
Or set your own review days
This is an illustration of the spacing effect, not a prediction of your own memory. The curve shape follows the research below; exact numbers depend on the material and the person.
How to read this
The dashed line is what happens after a single study session with no follow-up: retention drops fast, then keeps sliding. This is the forgetting curve that Hermann Ebbinghaus first measured in 1885 and that Murre and Dros replicated almost exactly in 2015. Most of what you learn once is gone within days.
The solid green line is your review schedule. Each review resets retention and, crucially, makes the next drop-off slower, so the gaps between reviews can grow over time. That is the spacing effect, one of the most robust findings in memory research: across 317 experiments, Cepeda and colleagues found spaced study reliably beats cramming, with the ideal gap growing as the length of time you want to remember grows.
Try the three presets. Cramming once leaves you near zero within a week. Massing four reviews into the first four days does better, but the reviews are wasted while retention is still high. A spaced schedule (something like days 1, 3, 7, 16 and 35) holds retention far higher for the same number of reviews. Spacing and self-testing are the only two techniques Dunlosky and colleagues rated high utility out of ten they reviewed.
If you want the full explanation behind the maths, read our guide to the forgetting curve and spaced repetition, or the primer on what microlearning is and why short daily lessons apply exactly this science.