〜ともなると (~to mo naru to) — once it comes to (a higher level) ~, naturally…

When a position, age or occasion reaches a higher or special level — 'at that point, of course things are different'.

Formula (सूत्र ढाँचा)

N + ともなると、…

Grammar rule (व्याकरण नियम र परिभाषा)

When to use it

A senior at your company who used to be like a friend has just become 部長. Now he is the first one in every morning and answers the phone even on holidays.
You think: 'Once you're a department head, the responsibility is something else.' — 「部長ともなると…」

Meaning

「〜ともなると」= 'reach that level and of course it's like this' — stressing 'this high / this special', with a touch of surprise or feeling.
What follows is the state that naturally comes with that level.

How to attach

Straight after a noun
The noun must be a higher position or age (社長・中学生・五十歳) or a special occasion (正月・祭り・決勝戦)
「〜ともなれば」says the same thing.

Versus what you know

The 「〜になると」you know just states a plain change (春になると暖かくなる).

Watch out

An ordinary Monday will not do.
No wish, request or order can follow (× 部長ともなると、頑張ってください).

Examples (उदाहरणहरू)

社長ともなると、休みの日でも仕事の電話がかかってくる。

しゃちょうともなると、やすみのひでもしごとのでんわがかかってくる。

Once you're the company president, work calls come even on your days off.

How it is built (कसरी बन्यो) 社長 = company boss (the top position) → attach 「ともなると」 directly = once you're actually the boss → then what's natural in that position: 休みの日でも電話がかかってくる = calls come even on days off.

年末ともなると、駅も店もどこも人でいっぱいだ。

ねんまつともなると、えきもみせもどこもひとでいっぱいだ。

When the year-end comes around, stations, shops — everywhere is packed with people.

How it is built (कसरी बन्यो) 年末 = the end of the year (a special time in Japan) → 「ともなると」 = once that time actually comes → then the natural scene: どこも人でいっぱいだ = crowds everywhere.

介護の仕事も五年目ともなると、新人に教える立場になる。

かいごのしごともごねんめともなると、しんじんにおしえるたちばになる。

Once you're in your fifth year of care work, you end up being the one who teaches the newcomers.

How it is built (कसरी बन्यो) 介護の仕事も = in care work, too (「も」 adds feeling) → 五年目 = fifth year (a higher stage of experience) → 「ともなると」 → then a natural change: 新人に教える立場になる = the role of teaching newcomers.

Knowledge check (मिनी ज्ञान जाँच)

Question: 1/3

「大企業の部長＿＿＿、責任の重さも全然違う。」— fill the blank.

💡 Hint: What naturally comes with a high position.