The mystery of「〜になります」: Grammatically incorrect but everyone uses it!

I'm sure when you're eating out or shopping in Japan, you've often heard staff say things like:

• 「こちら、コーヒーになります」(Kore, ko-hi- ni narimasu)
• 「お会計は千円になります」(Okaikei wa sen-en ni narimasu)

If translated word-for-word, the first sentence means "This WILL BECOME coffee" ☕️. Sounds strange, right? Why don't they just say「コーヒーです」(This is coffee)?

Welcome to one of the most interesting "national mistakes" in modern Japanese, also known as バイト敬語 (baito keigo - part-timer's honorifics).

🤔 Why is it "wrong"?

According to standard grammar, 「〜になります」 (ni narimasu) expresses a change of state.

• Example: 春になると、暖かくなります。(In spring, it becomes warm.)

Meanwhile, 「〜です」 or 「〜でございます」 is used to affirm an obvious fact.

Therefore, in theory, when a staff member brings you a cup of coffee that's already made, it IS coffee, not WILL BECOME coffee. Using「〜になります」in this case is incorrect.

💡 So why do Japanese people use it all the time?

This is where the subtlety (and trouble) of real Japanese comes in, where feeling and nuance are more important than textbook rules.

1. Sounds softer and more polite: Many Japanese people feel that saying「コーヒーです」directly is a bit abrupt and forceful. Adding「〜になります」acts as a cushion, making the sentence softer, more indirect, and more polite in a customer service context.

2. Creates a psychological "waiting" period: This way of speaking implies that "After I've prepared it and put it in front of you, this will be your coffee." It creates a seamless process from preparation to serving, which sounds more professional to many people.

3. Has become a "standard form" in the service industry: This way of speaking (although wrong) has been included in many training manuals for new employees (マニュアル) at convenience store chains, restaurants... to the point that it has become a habit and is considered the "correct" way to speak in the service industry.

✅❌ When to use and not to use?

As someone who has lived here for a long time and wants to communicate naturally, this is my advice:

• ✅ SHOULD USE: When you are in a service provider role (restaurant staff, store clerk) or when communicating in similar situations. This shows that you "understand the rules of the game."
• ❌ SHOULD NOT USE: In truly formal contexts such as speaking at a business meeting, writing a report, or emailing an important partner. In those cases, go back to the standard form of「〜でございます」or「〜です」to show professionalism and accurate vocabulary.

✨ Mastering nuances like「〜になります」is the key to moving from the level of "speaking correct grammar" to "communicating naturally and subtly" like a native speaker. It shows that you not only learn Japanese from books, but also truly live and breathe the culture here.