Flashcard Retention Calculator Formula

Understand the math behind the flashcard retention calculator. Each variable explained with a worked example.

Use the Flashcard Retention Calculator

Formulas Used

Retention Rate

retention_rate = (correct_recalls / total_cards) * 100

Cards Needing Review

cards_to_review = total_cards - correct_recalls

Cards Learned per Session

cards_per_session = correct_recalls / sessions

Variables

VariableDescriptionDefault
total_cardsTotal Flashcards100
correct_recallsCorrectly Recalled78
sessionsStudy Sessions Completed5

How It Works

How to Calculate Flashcard Retention

Retention rate measures how many flashcards you can recall correctly.

Formula

Retention Rate = (Correctly Recalled / Total Cards) x 100

Aim for 85–95% retention. Below 85% means you are reviewing too many new cards. Above 95% means you can add more.

Worked Example

A student has 100 flashcards, recalls 78 correctly after 5 study sessions.

total_cards = 100correct_recalls = 78sessions = 5
  1. 01Retention rate = (78 / 100) x 100 = 78%
  2. 02Cards needing review = 100 - 78 = 22
  3. 03Cards learned per session = 78 / 5 = 15.6

Frequently Asked Questions

What is a good flashcard retention rate?

Aim for 85–90%. This means you are being challenged but still retaining most material. Adjust new card intake to maintain this range.

How many new cards should I add per day?

Start with 10–20 new cards per day. Adjust based on your retention rate. If it drops below 80%, reduce new cards.

Should I study cards I already know?

Yes, periodic review prevents forgetting. Spaced repetition systems automatically schedule reviews at optimal intervals.

Ready to run the numbers?

Open Flashcard Retention Calculator