Study Schedule Optimizer Spaced Repetition Calculator
Calculate study schedule spaced repetition with our free tool. Get data-driven results, visualizations, and actionable recommendations.
Reviewed by Daniel Agrici, Founder & Lead Developer
Formula
R = e^(-t/S) | S_n = S_0 x 2.5^n
Retention (R) follows the Ebbinghaus forgetting curve where t is time since last review and S is memory stability. Each successful review multiplies stability by approximately 2.5 (based on SM-2 algorithm), making the memory last longer before decay. The optimizer calculates review intervals and allocates daily study time between new learning and reviews.
Worked Examples
Example 1: 30-Day Exam Prep with 20 Topics
Problem:A student has 20 medium-difficulty topics to learn in 30 days, studying 3 hours per day, targeting 85% retention.
Solution:First learning: 20 topics x 30 min = 600 min (10 hrs)\nReviews needed: ~5 per topic\nReview time: 20 x 5 x 12 min = 1,200 min (20 hrs)\nTotal study: 30 hrs | Available: 90 hrs\nNew topics per day: floor(90 x 0.5 / 30) = 1.5, so 1-2/day\nDays for new topics: ceil(20/1) = 20 days\nReview-only days: 10 days
Result:Feasible | 30 hrs needed / 90 hrs available | Learn 1-2 new topics/day + daily reviews
Example 2: Cramming 40 Hard Topics in 14 Days
Problem:A student has 40 hard topics in 14 days, studying 4 hours per day, targeting 80% retention.
Solution:First learning: 40 x 45 min = 1,800 min (30 hrs)\nReviews needed: ~5 per topic\nReview time: 40 x 5 x 18 min = 3,600 min (60 hrs)\nTotal study: 90 hrs | Available: 56 hrs\nUtilization: 160.7% (exceeds available time)\nAdjustment needed: reduce topics or increase daily hours
Result:Not Feasible | 90 hrs needed / 56 hrs available | Must prioritize or increase study time
Frequently Asked Questions
What is spaced repetition and why is it effective?
Spaced repetition is a learning technique where review sessions are scheduled at increasing intervals, timed to occur just before you would forget the material. It is based on the Ebbinghaus forgetting curve, which shows that memory decays exponentially without review. By reviewing at the optimal moment (when retention drops to about 70-80%), each review session strengthens the memory trace and doubles or triples the time before the next review is needed. Research shows spaced repetition can improve long-term retention by 200-400% compared to massed practice (cramming). The SM-2 algorithm, developed by Piotr Wozniak, is the most widely used implementation, powering tools like Anki and SuperMemo.
References
Reviewed by Daniel Agrici, Founder & Lead Developer · Editorial policy