-기 마련이다 (Bound to)

-기 마련이다 expresses natural consequence or inevitability. It means "bound to," "naturally," "sure to," or "it's natural that." It indicates something is expected or inevitable based on natural principles.

Structure

Verb/Adjective stem + -기 마련이다

Breakdown:

• -기: Nominalizing ending
• 마련: Natural arrangement, provision (noun)
• 이다: To be (copula)
• Combined meaning: "It's natural/inevitable that..."

Literal meaning: "It is the natural arrangement to [verb]"

Formation Rules

With All Verbs

Verb stem + -기 마련이다:

• 실수하다 → 실수하기 마련이다 (bound to make mistakes)
• 변하다 → 변하기 마련이다 (bound to change)
• 배우다 → 배우기 마련이다 (bound to learn)
• 늙다 → 늙기 마련이다 (bound to age)

With Adjectives

Adjective stem + -기 마련이다:

• 힘들다 → 힘들기 마련이다 (bound to be difficult)
• 외롭다 → 외롭기 마련이다 (bound to be lonely)
• 그립다 → 그립기 마련이다 (bound to miss)

Core Meaning: Natural Inevitability

Natural Consequence

Something naturally follows:

• 연습하면 늘기 마련이에요 (If you practice, you're bound to improve)
• 시간이 지나면 잊기 마련이에요 (As time passes, you're bound to forget)
• 사람은 실수하기 마련이에요 (People are bound to make mistakes)
• 모든 것은 변하기 마련이에요 (Everything is bound to change)

Universal Truth

General principle or law of nature:

• 살다 보면 힘든 일이 있기 마련이다 (In life, difficult things are bound to happen)
• 노력하면 보상을 받기 마련이다 (If you try, you're bound to be rewarded)
• 시작이 있으면 끝이 있기 마련이다 (If there's a beginning, there's bound to be an end)

Expected Outcome

Predictable result:

• 거짓말하면 들키기 마련이에요 (If you lie, you're bound to get caught)
• 게으르면 실패하기 마련이에요 (If you're lazy, you're bound to fail)
• 부지런하면 성공하기 마련이에요 (If you're diligent, you're bound to succeed)

Common Usage Patterns

Life Lessons

Expressing wisdom or general truths:

• 사람은 누구나 실수하기 마련이다 (Everyone is bound to make mistakes)
• 세월이 흐르면 변하기 마련이다 (As time flows, things are bound to change)
• 주는 만큼 받기 마련이다 (You're bound to receive as much as you give)

Consolation

Comforting someone:

• 처음엔 힘들기 마련이에요 (It's bound to be difficult at first)
• 외국에서는 외롭기 마련이에요 (You're bound to be lonely abroad)
• 실패도 있기 마련이에요 (There are bound to be failures)

Cause and Effect

Natural results of actions:

• 열심히 하면 성공하기 마련이다 (If you work hard, you're bound to succeed)
• 먹으면 배가 부르기 마련이다 (If you eat, you're bound to be full)
• 공부하면 알게 되기 마련이다 (If you study, you're bound to learn)

Conjugation

Present Tense

마련이다 + endings:

• -기 마련이에요 (is bound to - polite)
• -기 마련입니다 (is bound to - formal)
• -기 마련이야 (is bound to - casual)

Past Tense (Rare)

마련이었다:

• -기 마련이었어요 (was bound to)
• Less commonly used

With Modifiers

-(으)ᄅ 수밖에 없다 can replace in some contexts:

• 실수할 수밖에 없어요 (Can't help but make mistakes)
• Similar meaning, more about lack of alternatives

Negative Forms

Won't/Not Bound To

안 + Verb + -기 마련이다 (rare):

• Generally not used in negative form
• Use other patterns instead

Alternative expressions:

• -지 않을 수도 있다 (might not)
• -(으)ᄅ 리 없다 (there's no way)

Common Expressions

Universal Truths

• 사람은 실수하기 마련이다 (People are bound to make mistakes)
• 모든 것은 변하기 마련이다 (Everything is bound to change)
• 시간이 약이기 마련이다 (Time is bound to heal)

Life Wisdom

• 주는 만큼 받기 마련이다 (You receive as much as you give)
• 뿌린 대로 거두기 마련이다 (You reap what you sow)
• 좋은 날도 나쁜 날도 있기 마련이다 (There are bound to be good days and bad days)

Natural Processes

• 연습하면 늘기 마련이다 (If you practice, you're bound to improve)
• 시간이 지나면 잊기 마련이다 (As time passes, you're bound to forget)
• 나이 들면 늙기 마련이다 (As you age, you're bound to grow old)

Politeness Levels

Formal (합니다체)

• 실수하기 마련입니다 (is bound to make mistakes)
• 변하기 마련입니다 (is bound to change)

Polite (해요체)

• 실수하기 마련이에요 (is bound to make mistakes)
• 변하기 마련이에요 (is bound to change)

Casual (반말)

• 실수하기 마련이야 (is bound to make mistakes)
• 변하기 마련이지 (is bound to change)

Formal Register

Common in Written Korean

Often found in:

• Proverbs and sayings
• Formal writing
• Speeches
• Life advice
• Philosophical discussions

Comparison with Similar Patterns

-기 마련이다 vs -(으)ᄅ 수밖에 없다

-기 마련이다: Natural inevitability, general truth

• 사람은 실수하기 마련이다 (People are bound to make mistakes)
• Expresses natural law

-(으)ᄅ 수밖에 없다: No choice, necessity

• 실수할 수밖에 없었어요 (I had no choice but to make mistakes)
• Specific situation, lack of alternatives

-기 마련이다 vs -게 되다

-기 마련이다: Inevitable outcome, natural

• 시간이 지나면 잊기 마련이에요 (As time passes, you're bound to forget)
• General principle

-게 되다: Come to, end up

• 시간이 지나서 잊게 됐어요 (As time passed, I came to forget)
• Specific change in state

-기 마련이다 vs -는 법이다

-기 마련이다: Bound to happen naturally

• 실수하기 마련이다 (Bound to make mistakes)

-는 법이다: It's the rule/way

• 실수하는 법이다 (It's the way to make mistakes / That's how mistakes happen)

Note: Very similar meanings, often interchangeable

Common Mistakes

❌ Incorrect: 좋는기 마련이다

Wrong nominalizer form

✅ Correct: 좋기 마련이다

Use -기 for nominalization

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❌ Incorrect: 마련해요

Confusing with verb 마련하다 (to prepare)

✅ Correct: 마련이에요

마련이다 is a fixed pattern, not the verb 마련하다

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❌ Incorrect: 실수하기 마련했어요

Wrong conjugation

✅ Correct: 실수하기 마련이에요

마련이다 conjugates, not the main verb

Summary Table

Type	Form	Example	Meaning
Verb	-기 마련이다	실수하기 마련이다	Bound to make mistakes
Adjective	-기 마련이다	힘들기 마련이다	Bound to be difficult
Present	-기 마련이에요	변하기 마련이에요	Is bound to change
Casual	-기 마련이야	늙기 마련이야	Bound to age

Cultural Context

Philosophical Tone

Often used for:

• Life advice and wisdom
• Consoling others
• Explaining natural consequences
• Expressing acceptance of reality
• Teaching lessons

Formal Expression

Characteristics:

• More common in formal speech/writing
• Sounds wise and experienced
• Used by elders giving advice
• Found in proverbs

Usage Context Guide

Use -기 마련이다 when:

• Expressing universal truths
• Explaining natural consequences
• Offering consolation or reassurance
• Teaching life lessons
• Stating inevitable outcomes

Common contexts:

• Life advice (실수하기 마련이다)
• Consolation (처음엔 힘들기 마련이에요)
• Natural laws (변하기 마련이다)
• Cause and effect (노력하면 성공하기 마련이다)

Key Takeaways

• ✅ Natural inevitability: Bound to happen naturally
• ✅ Universal truths: General principles and laws
• ✅ Same form for all: -기 마련이다 regardless of verb
• ✅ Formal/wise tone: Sounds philosophical
• ✅ Common in advice: Used for life lessons
• ✅ Not commonly negative: Rare in negative form

-기 마련이다 is essential for expressing natural consequences, universal truths, and inevitable outcomes in Korean, particularly useful for giving advice and explaining life principles.