The Best Spaced Repetition Intervals for Vocabulary
There's no single perfect number — but there is a reliable shape: gaps that keep growing.
Once you know spaced repetition works, the obvious question is: how long should the gaps actually be? A day? A week? The honest answer is that a good range matters more than a magic number — and the range is easy to remember.
Here's a practical set of intervals for vocabulary, why they grow, and how to bend them to fit real life.
Key takeaways
- A dependable sequence: 1 day → 3 days → 1 week → 2 weeks → 1 month → 3 months+.
- Each gap roughly doubles as long as you keep recalling correctly.
- Miss a word and it drops back to a short interval.
- Exact numbers matter less than the growing shape and staying consistent.
Why the gaps should grow
The first time you meet a word, its memory is fragile, so it needs a review soon. Each successful recall strengthens it and makes it fade more slowly — so the next review can safely wait longer. Keep succeeding and the gaps stretch from days to weeks to months. That expanding rhythm is what makes spaced repetition so efficient: strong words barely cost you any time, while weak words get the attention they need.
A practical interval sequence
This sequence works well for most vocabulary. Treat it as a guide, not gospel:
| Review # | Interval after last | Roughly |
|---|---|---|
| 1 | Same day | Hours later |
| 2 | 1 day | Tomorrow |
| 3 | 3 days | This week |
| 4 | 1 week | Next week |
| 5 | 2 weeks | Mid-month |
| 6 | 1 month | Next month |
| 7 | 3 months+ | Long-term |
If you're running a paper Leitner box, each row is roughly one box. If you use an app, this is close to what it does automatically behind the scenes.
Don't chase the perfect interval. Chase the growing gap, and stay consistent.
Adjusting for hard and easy words
Not every word deserves the same treatment. A word you nail instantly can skip ahead — jump it two intervals instead of one. A word you keep fumbling should come back sooner; reset it to the first interval and let it climb again. Most apps offer "easy / good / hard" buttons that do this for you. Doing it by hand is just as valid: right answers move forward, misses go back.
Fitting it into real life
You won't always review on the exact day, and that's fine. A review a day or two late still works; the intervals are targets, not deadlines. The bigger risk is skipping the early, short intervals — those are the ones that rescue a new word before it's lost. Protect the first few reviews, and be relaxed about the long ones.
Frequently asked questions
A common, effective sequence is 1 day, 3 days, 1 week, 2 weeks, 1 month, then a few months. Each gap roughly doubles as long as you keep recalling correctly.
No. Easy words can jump ahead faster, and words you keep missing should return sooner. Apps adjust automatically; by hand, send missed cards back to the start.
Too early wastes time on words you know; too late means relearning. Aim to review just as recall starts to feel effortful.
Get the timing right, effortlessly
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The VocabVaultz team
We're language learners who got tired of forgetting words we'd "already learned." Everything here is a method we've actually tried on our own vocabulary. More about us →
