Use です/ます with anyone outside your inner circle, like bosses, teachers, strangers, or new coworkers. Use plain form with people already inside it, like close friends and family. The switch tracks relationship status, not how friendly you feel.
This guide is for N5-N4 learners who know both forms but hesitate on which to use. After reading, you’ll have one simple test to pick the right form every time.
Quick summary: です/ます is for people outside your inner circle, while plain form is for people already inside it — the choice depends on role, not affection.
| Relationship | Default Register | Typical Ending |
|---|---|---|
| Boss, teacher, client | Polite (です/ます) | 〜ます / 〜です |
| Coworker you’re not close to | Polite (です/ます) | 〜ます / 〜です |
| Close friend, same age | Casual (plain form) | 〜る / 〜た / 〜ない |
| Family member | Casual (plain form) | 〜る / 〜た / 〜ない |
| Stranger (clerk, station staff) | Polite (です/ます) | 〜ます / 〜です |
- Why です/ます Isn’t Just “Formal English” in Your Head
- The One Question That Tells You: です/ます or Plain Form?
- です/ます for Anyone Outside Your Inner Circle
- Plain Form for the People Already Inside Your Circle
- When the Line Moves: Mixing です/ます and Plain Form in the Same Conversation
- FAQ: Polite Form vs Casual Form in Japanese
- Quick Quiz: Choose the Right Form
- Summary: Picking Polite or Plain Form
Why です/ます Isn’t Just “Formal English” in Your Head
The English Habit That Misleads You: Politeness as Word Choice, Not Verb Form
In English, you get polite by picking softer words. The sentence structure underneath stays the same, so you expect tone alone to handle formality in Japanese too.
Japanese builds formality into the verb ending itself. Every single sentence makes this choice, not just the sentences that feel important.
English speakers already soften language for strangers and bosses, saying “Could you possibly…” instead of “Can you…”. But once you’re comfortable, the sentence structure underneath never actually changes. Japanese politeness lives inside the verb ending itself, so comfort alone can’t make it disappear.
In English, a close relationship with someone above you, like an easygoing professor, can erase formality completely. In Japanese, that same senior status usually keeps です/ます in place, no matter how warm the relationship feels.
The One Question That Tells You: です/ます or Plain Form?
Status and Distance, Not How Much You Like Someone
Is this person inside my circle — a close friend or family — or outside it, like a boss, teacher, coworker, or clerk? Inside, plain form. Outside, です/ます.
Say a coworker you’ve had lunch with every week for a year asks about a deadline. The lunches don’t move them inside the circle, so です/ます stays.
Liking someone doesn’t move them into your inner circle by itself. Feeling comfortable with your manager still doesn’t make です/ます optional.
です/ます for Anyone Outside Your Inner Circle
Coworkers, Teachers, and Strangers Default to Polite, Even When Friendly
Default to です/ます with coworkers, teachers, store staff, and anyone you just met. This applies regardless of how warm the interaction feels.
Polite form here shows respect for the relationship’s structure. It doesn’t mean you feel distant from the person.
Japanese: 忙しいところすみません、これ、今日中に送っていただけますか？
Romaji: Isogashii tokoro sumimasen, kore, kyou juu ni okutte itadakemasu ka?
English: Sorry to bother you when you’re busy — could you send this by the end of today?
Why: Shows the polite request form (〜ていただけますか) that stays the default even between coworkers who get along well.
Japanese: 先生、この漢字の読み方、教えていただけますか？
Romaji: Sensei, kono kanji no yomikata, oshiete itadakemasu ka?
English: Could you tell me how to read this kanji?
Why: A teacher sits outside your circle, so the request stays polite no matter how approachable they are.
Plain Form for the People Already Inside Your Circle
Family, Close Friends, and Texting Default to Plain Form
With close friends, family, and people you’re already close to, plain form is the natural default. It isn’t a shortcut you earn over time.
Switching to polite form with them can sound sarcastic or cold. It can feel like you’re deliberately creating distance.
Plain form is also the everyday default for diaries and personal notes. This holds regardless of whether anyone else will read them.
Japanese: 明日ひま？ごはん食べに行かない？
Romaji: Ashita hima? Gohan tabe ni ikanai?
English: Free tomorrow? Want to go grab food?
Why: ひま and 行かない are plain forms — with a close friend this is the default, not a shortcut you earn.
Japanese: お母さん、今日の晩ごはん何？
Romaji: Okaasan, kyou no bangohan nani?
English: Mom, what’s for dinner tonight?
Why: Family sits inside your circle, so the sentence can end on a bare 何 with no です attached.
When the Line Moves: Mixing です/ます and Plain Form in the Same Conversation
Why One Speaker Can Use Both Within a Single Exchange
Speakers sometimes drop plain form inside an otherwise polite sentence. This happens for quoted thoughts or quick asides, and it isn’t a mistake.
A senior person can speak casually to a junior, while the junior keeps replying in polite form. The relationship isn’t symmetrical, so the forms don’t have to match.
Unnatural: 課長、明日の会議、資料できた？
Natural: 課長、明日の会議の資料、できましたか？
English speakers treat casualness as a reward for feeling comfortable with someone. Warmth toward a boss gets mistaken for permission to drop polite endings.
Common Mistake: Learners assume polite form is always the safe choice. With a close friend, 今度の休み、一緒に出かけますか？ can sound cold instead — say 今度の休み、一緒に出かける？ instead.
FAQ: Polite Form vs Casual Form in Japanese
Can I use plain form with a boss if we are close outside work?
Generally, no — the boss relationship keeps です/ます in most work contexts. Closeness outside work doesn’t erase the role inside it.
Is polite form ever too formal with a stranger?
Polite form is typically the safe default with strangers like clerks or station staff. It rarely sounds too distant in these short, one-time interactions.
Why do some speakers mix polite and plain form in one conversation?
A senior speaker can use plain form toward a junior while the junior stays polite. The relationship isn’t equal, so the forms naturally differ.
Quick Quiz: Choose the Right Form
Test yourself with these three short scenarios.
- Your close friend asks about weekend plans. Do you say 出かけますか or 出かける?
- Your boss asks if the report is ready. Do you say できた? or できましたか?
- A store clerk asks if you need a bag. Is this a polite-form or plain-form situation?
1. 出かける – A close friend is inside your inner circle, so plain form feels natural.
2. できましたか？ – A boss stays outside your inner circle, so keep です/ます.
3. Polite form – Strangers like store staff generally get です/ます, even in a quick exchange.
Summary: Picking Polite or Plain Form
- です/ます is the default outside your inner circle: bosses, teachers, strangers, new coworkers.
- Plain form is the default inside your inner circle: close friends and family.
- The choice tracks relationship status, not personal comfort or affection.
- One speaker can mix both forms when the relationship isn’t symmetrical.
Once this test feels automatic, you’re ready to look at how keigo adds extra layers for work and formal situations. That’s a natural next step after this basic line feels clear.
