Memory Digest

Spaced Repetition

Spaced repetition means reviewing information at growing intervals; it is one of the best-proven ways to remember things long term, and anyone can use it with paper, cards or a free app.

Last reviewed: October 2026

If you want to remember something for months instead of days, when you review it matters as much as how much you review it. Spaced repetition is the simple idea of going over information several times, with longer and longer gaps in between. It is one of the most solidly proven findings in all of memory science.

The forgetting curve

In the 1880s, German psychologist Hermann Ebbinghaus memorized lists of nonsense syllables and tested himself over time. He found that forgetting is fast at first and then slows down. Much of what we learn fades within a day or two unless we go back to it. In 2015, Dutch researchers repeated his experiment and got a very similar curve, more than 125 years later. (Read more in why we forget.)

Ebbinghaus also found the fix: each time you review, the memory fades more slowly. So the gaps between reviews can get longer and longer.

What the research shows

Spacing beats cramming. A large 2006 review by Nicholas Cepeda and colleagues pulled together hundreds of experiments. People who spread their study out over time remembered much more later than people who studied the same amount in one block. This is called the spacing effect.

The best gap depends on how long you need to remember. The same review found that if you need to remember something for a long time, longer gaps between reviews work better. A few minutes apart is fine for tomorrow. Days or weeks apart is better for next year.

Testing yourself makes it stronger. Spaced repetition works best when each review is a quiz, not a reread. Trying to pull the answer out of memory, even if you struggle, strengthens it more than looking at it again. A major 2013 review of study methods by John Dunlosky and colleagues rated two techniques as highly useful: practice testing and spacing out practice. Popular habits like rereading and highlighting rated low.

These benefits have been seen in children, college students and older adults.

How to do it

You don't need special equipment.

A simple schedule. After learning something, review it:

1. Later the same day
2. The next day
3. A few days later
4. About a week later
5. About two to four weeks later
6. Every month or two after that, if it still matters

If you get something wrong, start that item's schedule over with short gaps.

Flashcards in boxes (the Leitner system). Put flashcards in box 1. Review box 1 every day. When you get a card right, move it to box 2, which you review every few days. Right again, box 3, reviewed weekly. Get one wrong and it goes back to box 1. Hard cards come up often, easy ones rarely.

Free apps. Programs such as Anki and many language apps do the scheduling for you. They show each card just before you're likely to forget it.

For everyday life. You can use the same idea without cards:

• Names: think of a new person's name a minute after meeting them, again when you leave, and again that evening (see Remembering Names).
• A new phone number or PIN: recall it a few times over the next few days instead of repeating it ten times right away.
• A grandchild's birthday, a new medication name, a church member's name: quiz yourself now and then.

Tips that help

• Quiz, don't reread. Cover the answer and try to recall it first.
• Keep sessions short. Ten or fifteen minutes a day works better than an hour once a week.
• Make cards small. One fact per card.
• Say it out loud or explain it. Putting something in your own words helps it stick.
• Get enough sleep. Sleep helps lock in what you learned (see Sleep and Memory).

Can it help people with memory loss?

A related approach called spaced retrieval is used by speech-language therapists with people who have mild cognitive impairment or early dementia. The person practices recalling one useful piece of information, such as where their calendar is or a safe-swallowing step, at gradually longer intervals. It doesn't slow the disease, but it can help someone hold on to a few key facts or routines. Ask a doctor about a referral to a speech-language pathologist if this sounds useful. See also Memory Aids and Tools.

The bottom line

Review a little, often, with longer gaps, and test yourself rather than rereading. It's simple, free, and works at any age.

This article is for general information and is not a substitute for advice from your own doctor.

Sources

1. Cepeda NJ et al. Distributed practice in verbal recall tasks: A review and quantitative synthesis. Psychological Bulletin, 2006
2. Dunlosky J et al. Improving Students' Learning With Effective Learning Techniques: Promising Directions From Cognitive and Educational Psychology. Psychological Science in the Public Interest, 2013
3. Murre JM, Dros J. Replication and Analysis of Ebbinghaus' Forgetting Curve. PLoS One, 2015

Not medical advice. This article is general information, not a diagnosis or treatment plan for any individual. Talk with a doctor about your situation.

Related articles

• How to Improve Your Memory
• Why We Forget
• Memory Techniques: Mnemonics and Memory Palaces
• Learning New Skills at Any Age
• Remembering Names