Study lab / spacing

Same six study sessions. One plan keeps the facts for months, the other loses them in days.

Your exam is in 30 days. You have time for exactly 6 sessions. Pick the plan you think holds up best, then check how much you would still remember 60 days after the exam.

Workshop

Build your own plan

Tap a day to add a session (tap again for a second one that day). You have 6 sessions left. The last box is exam morning.

Recall on exam day0%

Recall 60 days later0%

your predicted recall| exam dayticks on the bottom: study sessions

Why it works

Forgetting is fast, then slow. Each review flattens the curve.

In 1885 Hermann Ebbinghaus memorised lists of nonsense syllables and measured how much effort he saved when relearning them later. His own numbers fall steeply in the first hour and then crawl. The line is a power-law fit to those seven points.

After	Savings
20 minutes	58.2%
1 hour	44.2%
8.8 hours	35.8%
1 day	33.7%
2 days	27.8%
6 days	25.4%
31 days	21.1%

Modern work confirms the spacing side. Cepeda and colleagues (2008) tested 1,354 people on trivia facts across gaps from minutes to 105 days. The best gap between sessions was not fixed: it was roughly 10 to 20 percent of the time until the test, and being a bit too long hurt far less than being too short.

Test after	Best gap
7 days	about 1 day
35 days	about 11 days
70 days	about 21 days
350 days	about 21 to 28 days

How the simulator works

A deliberately simple model, not a prediction for you. Memory strength S starts at 1 day and recall is e^(-t/S). Each session multiplies S by 1.4 + 2.6 x (how much you had forgotten), so a review that rescues a fading memory helps most and repeating something you still remember fully helps little. That one rule is enough to reproduce the cramming trap. Real memory curves are not exact exponentials, which is why the Ebbinghaus fit above is a power law.

Sources: Ebbinghaus, H. (1885) Memory: A Contribution to Experimental Psychology (savings figures as tabulated in the 1913 English translation, psychclassics.yorku.ca). Cepeda, N.J., Vul, E., Rohrer, D., Wixted, J.T., Pashler, H. (2008) Spacing effects in learning, Psychological Science 19(11), 1095-1102, doi:10.1111/j.1467-9280.2008.02209.x. Gap values rounded from the paper's optimal-gap table.