Forgetting Curve Visualizer
Memory retrievability decays exponentially, R = exp(−t/S) — the famous Ebbinghaus forgetting curve. Each review resets the curve to 100% and, thanks to the spacing effect, multiplies the stability S so the next decay is slower. A shaded sweet-spot band (70–90% recall) marks desirable difficulty: each marker is labelled early, on time, or late from where it lands. Pick a preset schedule or click to place reviews and drag markers to retarget them.
Runs 100% in your browser — simulations are computed locally on your device.
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Notes
- Ebbinghaus published the first forgetting curves in 1885 by memorizing nonsense syllables and re-testing himself — the exponential shape has held up remarkably well.
- Expanding intervals (1, 3, 7, 14 days…) beat massed reviews with the same number of repetitions because each review lands when it strengthens the memory most.
- Click empty chart space to add a review, drag a marker to move it, click a marker to remove it. The small dot on the curve shows recall just before that review.
- Runs 100% in your browser — nothing you type or practice leaves your device.
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