How Many New Words Should You Learn a Day?

Most people pick a number that feels ambitious, hold it for three weeks, and then quietly stop. The number is rarely the problem on day one — it is the review load it creates on day thirty.

The arithmetic nobody mentions

Spaced repetition does not only add the cards you make today. Every new word comes back several times over the following weeks, so your daily review count is a running total of every decision you have made so far.

A rough sense of the steady state: each new word generates somewhere around eight to ten reviews spread over its first month. So a habit of 20 new words a day settles into a queue of well over a hundred reviews daily, before you have read anything or learned anything new. That is a 40-minute session every single day, indefinitely.

At 5–10 new words a day the same arithmetic produces a queue most people can clear in ten or fifteen minutes. It looks unambitious. It is the reason some people are still going a year later.

Why the ambitious number backfires

The failure is not usually dramatic. It goes like this: a few busy days leave a backlog, the backlog makes opening the app feel like a chore, the chore gets postponed, and the backlog doubles. Within a fortnight the queue is unrecoverable and the sensible-looking move is to start again from scratch — which is where most abandoned decks come from.

A smaller daily number is not a compromise. It is what keeps the queue clearable on the day you are tired, travelling or busy, which is the only test that matters.

What to aim for

• 5 a day if you have about ten minutes. Roughly 1,800 words a year, which is past HSK 3 or JLPT N4 territory.
• 7 a day for around fifteen minutes. This is the sweet spot for most people with jobs.
• 10 a day if you genuinely have half an hour, every day, including the bad ones.
• 20+ only for a fixed sprint with an end date — an exam in eight weeks — and never as a permanent setting.

Those are the defaults InputDojo sets from the daily time you choose during setup, for exactly this reason: the number should follow the time you actually have, not the time you hope to have.

Which words are worth a slot

If you are only adding five a day, the choice matters more than the count. In order of value:

1. Words that recur in what you are reading. A word met three times in one article is already earning its place.
2. High-frequency vocabulary. The first 1,000 words of any language cover a startling share of ordinary text.
3. Words from your own material. Something met in an article you chose is anchored to a memory. The same word from a pre-made list is not.

What is rarely worth a slot: proper nouns, technical vocabulary outside your field, and anything you only recognise because it appeared in a list of words you were told to learn.

The honest test

After a month, ask one question: can you clear the day's reviews on your worst day? If yes, you can afford to add more. If no, the number was never sustainable, and reducing it now is cheaper than rebuilding the habit in six weeks.