Spaced repetition schedule

How the review dates are set

Spaced repetition means reviewing material at growing intervals instead of all at once. This calculator uses a fixed, widely used ladder: the first review one day after learning, then on day 3, day 7, day 14, day 30 and day 60, each counted from the original study date. For every step it adds the number of days to your date, shows the weekday, and marks whether that review is past, due today or still ahead.

Example: you study a chapter on Monday, March 2, 2026. The reviews fall on Tuesday March 3, Thursday March 5, Monday March 9, Monday March 16, Wednesday April 1 and Friday May 1. At 15 minutes per review the whole schedule costs 1 hour 30 minutes of review time spread over two months.

The gaps roughly double each time. That pattern follows from the forgetting curve first measured by Hermann Ebbinghaus in 1885: memory fades fastest in the first hours and days after learning, and each successful retrieval makes the next decline slower, so the next review can wait longer.

Using the schedule well

A review should be a test, not a reread. Cover your notes and try to recall the key points, solve a problem or answer flashcards, then check what you missed. Retrieval is effortful, and that effort is what strengthens the memory. Rereading feels easier but produces a false sense of knowing the material.

If you miss a date, do the review as soon as you can and keep the later dates as they are; one late review is far better than abandoning the ladder. If a review shows you have forgotten most of it, treat that day as a new learning date and start the schedule again. For exams, work backwards: material learned less than 30 days before the exam will not reach the later steps, so schedule your most important topics early enough for at least four reviews. Flashcard apps run adaptive versions of this idea that adjust each card's interval to your answers, but a fixed ladder like this one is enough for notes, chapters and lecture material.