-기 마련이다
is bound to; only natural
Another of the fixed -기 patterns. States that something is inevitable in the nature of things — the twin of -(으)ㄴ/는 법이다.
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When to use it
Attach -기 마련이다 to any stem — no vowel rule, ㄹ stays, no tense in front. The variant -게 마련이다 is equally correct and equally common.
It claims that something follows from how the world works: 사람은 누구나 실수하기 마련이에요. Often it is offered as consolation — the mistake was not your failing but the human condition.
Like 법이다, it cannot describe a single event. 어제 늦기 마련이었어요 is not possible.
Between the two, 법이다 states a rule and 마련이다 states an inevitability. In practice speakers use them interchangeably, and either sounds natural in most sentences.
How to attach it
| Situation | Form | Example |
|---|---|---|
| Any verb or adjective | -기 마련이다 | 실수하다 → 실수하기 마련이에요 |
| Equivalent variant | -게 마련이다 | 실수하게 마련이에요 |
| ㄹ stems keep the ㄹ | -기 마련이다 | 힘들기 마련이에요 |
| 이다 | -이기 마련이다 | 처음이기 마련이에요 |
| Never takes tense | plain stem only | 실수했기 마련이다 is wrong |
| Not for | single events | 어제 늦기 마련이었다 is wrong |
In use
사람은 누구나 실수하기 마련이에요.
Everybody makes mistakes — it’s only human.
처음에는 누구나 서툴기 마련입니다.
Everyone is clumsy at first, naturally.
시간이 지나면 잊히기 마련이지요.
Things fade with time, as they do.
급하게 하면 실수가 생기게 마련이에요.
Do it in a hurry and mistakes are bound to creep in.
직접 만들면 시간이 오래 걸리기 마련이에요.
Making it yourself is bound to take longer.
힘든 일도 언젠가는 끝나기 마련이다.
Even hard times come to an end eventually.
Compared with
-(으)ㄴ/는 법이다
법이다 frames the claim as a rule; 마련이다 frames it as something bound to happen. Most sentences accept either.
실수하는 법이다. (that’s the rule) / 실수하기 마련이다. (it’s bound to happen)
-기 십상이다
십상이다 also predicts a likely outcome, but a bad one, and it warns rather than consoles.
실수하기 마련이에요. (it happens to everyone) / 실수하기 십상이에요. (you’re likely to slip up)
당연히
The adverb asserts obviousness directly. 마련이다 builds it into the predicate and sounds more reflective.
당연히 힘들어요. / 힘들기 마련이에요.
Watch out
어제 늦기 마련이었어요.
어제는 늦을 수밖에 없었어요.
마련이다 states a general inevitability. A single past event needs a different construction.
사람은 누구나 실수했기 마련이에요.
사람은 누구나 실수하기 마련이에요.
-기 never carries tense. The claim is timeless, so the plain stem is all that is needed.
처음기 마련이에요.
처음이기 마련이에요.
A noun needs the copula 이다 first, as with -기도 하다 and -거든요.
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