Korean spelling check before sending a report: 6 common mix-ups

This one is for people who write reports and emails in Korean: Korean colleagues, learners working at Korean companies, and developers who review Korean UI text or documentation. A handful of spelling pairs come up again and again in workplace writing, and they are exactly the kind of mistake a reader spots in the first line.

The point isn't to memorise grammar. It's to have a short list you scan for before you hit send, the same way English writers check "its/it's" or "affect/effect".

TL;DR: check these six before sending: 되/돼, 안/않, 로서/로써, 결재/결제, 금세, 며칠.

Each rule below was checked against the National Institute of Korean Language's Standard Korean Dictionary and the official Korean spelling rules (한글 맞춤법).

The six pairs

1. 되 / 돼. Try replacing it with 되어. If 되어 fits, write 돼.
   이대로 진행하면 돼요 works because 되어요 also works. 돼 is just the contraction of 되어; 되었다 → 됐다 follows the same rule.

2. 안 / 않. If you can expand it to 아니, use 안. If it expands to 아니하, use 않.
   회의에 안 갔다 ("didn't go to the meeting") vs. 회의에 가지 않았다. 안 is short for 아니; 않다 is short for 아니하다.

3. 로서 / 로써. 로서 marks a role or status, 로써 marks a means or tool.
   팀장으로서 말씀드리면 ("speaking as team lead") vs. 대화로써 풀었다 ("solved it through conversation").

4. 결재 / 결제. 결재 is approval of a document by a superior; 결제 is payment.
   부장님 결재를 받았다 ("got the manager's sign-off") vs. 법인 카드로 결제했다 ("paid with the company card"). In an office, mixing these up changes the meaning.

5. 금세, not 금새. It's a contraction of 금시에 ("right away"), so it ends in 세.
   자료는 금세 보내 드릴게요.

6. 며칠, not 몇일. Article 27 of the spelling rules says to write it as it sounds: 며칠.
   며칠까지 보내 드리면 될까요?

How to use the list

• Keep it in your notes app and read through for these pairs before sending anything important. Two of them can be found with a plain search (Ctrl + F): 금새 and 몇일 are always wrong.
• Spell checkers catch some of these but not all, because both spellings of a pair are real words. 결재 and 결제 are both correct Korean; only the context tells you which one you meant.
• If you're reviewing Korean strings in a codebase, the same list works as a checklist for UI copy and error messages.

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Written with AI assistance. The spelling rules were checked against the National Institute of Korean Language's dictionary and spelling rules.