How Many Words Do You Need to Know to Read in English or Korean?

The question everyone asks wrong

"How many words do I need?" sounds like it has a clean number for an answer, so people go looking for one — 3,000 words, 5,000 words, 10,000 words. Those numbers exist and they're useful, but they answer a slightly different question than the one that actually determines whether you can read something: not how many words do you know in total, but what percentage of the words on this specific page do you already know.

The percentage that actually predicts comprehension

Reading research generally puts comfortable comprehension somewhere around 95–98% known words — one unknown word in every twenty to fifty. Below that, too many gaps appear too close together, and you spend more energy reconstructing meaning than absorbing it. Above it, almost nothing is new, which feels safe but teaches you very little.

This is why the same learner can read one book easily and find another, at a similar "level", genuinely hard — it was never really about the book's difficulty in the abstract. It's about how much of that book's specific vocabulary happens to overlap with what they already know.

Roughly, what that takes in word families

A "word family" bundles a base word with its close relatives — read, reads, reading, reader count as one, not four. As a rough guide for fiction, not an exact rule:

• ~1,000–1,500 word families gets you through most A1–A2 graded readers comfortably.
• ~2,500–3,000 gets you through B1 — genuine short stories, simple novels.
• ~4,000–5,000 gets you through B2 — lightly adapted classic literature, most everyday writing.
• 8,000+ is roughly where unabridged native fiction opens up, jokes, idiom and all.

Why this is good news, not a wall to climb

Word frequency is extremely lopsided: a small set of the most common words covers a huge share of any ordinary text, and each additional thousand words you learn buys you less coverage than the last. That front-loaded curve is exactly why starting at A1 and reading a lot of it is such an efficient use of time — the first thousand words you truly know are worth far more, page for page, than the next five thousand.

It's also why a level chosen well feels almost easy: at 95–98% known words, most of what's on the page is already yours. The handful of new words are doing the actual teaching, one at a time, surrounded by things you already understand.

The shortcut: let level do the counting for you

You never actually need to count your vocabulary. A story labelled at the right CEFR level is, by construction, sitting near that 95–98% band for someone genuinely at that level — that's what the label is promising. If a page feels like a wall of unknowns, that's the level talking, not a verdict on your ability; drop down and the same story will likely read at that comfortable percentage.

Watch it directly, too: if you're tapping the dictionary more than once or twice a paragraph, you're below the band for that text. If you never tap it at all, you're probably above it and could move up.

Growing the number without ever counting it

The words that move your real count are the ones you meet in context, tap once, and see again a few days later — not the ones memorized off a frequency list in isolation. Every word you tap while reading on SeoJae Story can be saved straight to your study plan, where spaced repetition resurfaces it right before you'd otherwise forget it.

Read enough stories at the right level and the count takes care of itself — you won't feel yourself crossing from 1,000 to 1,500 words, you'll just notice the next level down stops needing the dictionary at all.

Where to start

If you're not sure where your line currently sits, the two-minute check in CEFR levels explained finds it fast. Then open the library at that level, or browse classic stories retold at your level, and let the reading do the counting.