Spaced Repetition

This page covers how spaced repetition works in Fresh Cards and how to configure it. See this page for more general information on spaced repetition.

Fresh Cards uses a spaced repetition algorithm to ensure you’re only reviewing cards when their memories are fading.

This algorithm is written in JavaScript and Fresh Cards actually lets you write your own.

How does card scheduling work?

As you mark cards as correct or incorrect in a review, they are each assigned a score from 1 to 5. That score is used to determine when the card will be reviewed next.

As you continue to get good scores (3.0-5.0) on a card, the number of days until the next review will grow. This is meant to match how well your memory is able to remember information. (See the forgetting curve article on wikipedia for more info.) Over time and with practice, memories will get strong enough that you won’t need to practice them as frequently.

This system where the app increases the review time as you get better is called spaced repetition. Fresh Cards uses a variant of the SM-2 algorithm to schedule review times for cards.

In practice, a card’s reviews times will generally follow the schedule below. If a card is incorrectly answered at any point, the schedule will reset itself. (Note that the intervals between reviews may increase or decrease slightly as the system determines how easy or hard you are finding a card.)

1st review of a card (Day 0)
2nd review of a card - 1 day later
3rd review of a card - 6 days later
4threview of a card - 16 days later
5th review of a card - 40 days later
6th review of a card - 100 days later
7th review of a card - 280 days later

If you are curious to see a given card’s schedule, in the card list tab, double-click the card in the macOS version or tap it on iOS version. You’ll be taken to a card info screen where you can view a full timeline of all the reviews.

Simulating the scheduler

If you really want to geek out, be sure to check out the spaced repetition simulator. This allows you to see the effects of scores on the schedule of a single card.

Customizing the spaced repetition algorithm

Fresh Cards allows you to

To use the algorithm, you must go into a deck’s settings to pick it from the list.

Learn how to write your own spaced repetition algorithm.