What is FSRS Desired Retention and what should I set it to?

Desired Retention is the percentage of cards you expect to recall when they are scheduled for review. For high-stakes exams like USMLE Step 1 and Step 2 CK, 0.88 to 0.90 (88%–90%) is the consensus recommendation. If you are overwhelmed during heavy clinical rotations, reducing it to 0.84–0.85 can reduce daily review count by over 30% with minimal impact on exam recall.

Why does increasing retention from 90% to 95% cause review overload?

Human memory follows an exponential forgetting curve. Retaining the final 5% of memory requires seeing cards exponentially more frequently. Bumping retention from 90% to 95% almost doubles your daily review burden for a marginal 5% gain in factual recognition.

How do I change Desired Retention in Anki Desktop?

Open Anki Desktop, click the gear icon next to your deck, click Options, scroll down to the "Advanced" section where FSRS is enabled, locate "Desired Retention", enter your target decimal (e.g. 0.88 or 0.90), and click Save.

Do I need to change learning steps when using FSRS?

Yes. In modern FSRS, your learning steps should be short and within the same day—typically just a single step of "10m" or "15m". Do not use multi-day learning steps like "1d 3d", because FSRS takes over optimal inter-day scheduling starting on Day 1.

Spaced Repetition Ergonomics

Anki FSRS Target Retention & Review Time Calculator

Discover how much study time you can save by calibrating your Free Spaced Repetition Scheduler (FSRS) parameters. Simulate daily review volume, weekly hours, and board exam retention across USMLE, shelf exams, and the MCAT.

Select Exam or Study Scenario Preset

Simulation Parameters

FSRS-4.5 / 5.0 Math

Desired Retention (Target)90%

80% (Extreme Speed)88-90% (Sweet Spot)95% (Max Recall)

New Cards Per Day25 cards

Active Deck Size (Total Cards In Circulation)15,000 cards

Average Speed Per Card8 seconds

Calculated Review Workload

350reviews / day

Daily Study Time

47 min/day

(5.5 hrs/week)

Time Delta vs 90%

+0h

0% fewer reviews

Cognitive Efficiency Verdict

Optimal Board Balance: 90% retention is the evidence-based sweet spot for USMLE exams. You maintain strong diagnostic recall without hitting exponential review fatigue.

Target Retention Trade-Off Matrix

See how your daily workload changes as you adjust your target retention under FSRS:

Target Retention	Daily Reviews	Daily Study Time	Monthly Commitment	Recommendation
80%	165 reviews	22 min/day	11 hrs/mo	Extreme triage / short rotations
85%	227 reviews	30 min/day	15 hrs/mo	Clerkship sweet spot (30% time saved)
90%	350 reviews	47 min/day	23.5 hrs/mo	Gold standard for Step 1 & Step 2 CK
95%	719 reviews	96 min/day	48 hrs/mo	Diminishing returns / severe review overload

Ready to audit your actual deck?

Upload your .apkg or sync Anki Desktop in 1-click to measure your True Retention and eliminate leeches.

FSRS Mathematical Principles

Understanding the Retention vs. Review Volume Curve

In cognitive psychology, the relationship between target retrievability and review frequency is non-linear. As you approach 100% retention, memory decay requires review intervals to become exponentially shorter.

By dialing retention back from 90% to 85%, you accept a 5% drop in immediate recall while cutting your daily flashcard workload by nearly a third—freeing up 20+ hours a month for clinical question banks (UWorld, Amboss) and practical problem solving.

Frequently Asked Questions