What do krap and ka mean in Thai?

The short answer

Thai doesn't make a sentence polite by changing its grammar, the way English does with "could you possibly...". It adds a small word at the end. ขอบคุณkàwp-kun is "thank you"; ขอบคุณครับkàwp-kun kráp or ขอบคุณค่ะkàwp-kun kâ is "thank you" said politely. The particle carries no meaning of its own, only the tone of voice: respectful, warm, not curt.

The choice depends on who is speaking, not who you're talking to:

• Men: ครับkráp after everything.
• Women: ค่ะkâ after statements, คะká after questions.

So a man greets everyone with สวัสดีครับsà-wàt-dii kráp and a woman greets everyone with สวัสดีค่ะsà-wàt-dii kâ, whether the other person is a man, a woman or a child.

Krap (ครับkráp): for men

ครับkráp has a high tone and a short vowel, and it ends in an unreleased p: your lips close and the sound stops there. In relaxed speech many Thais drop the r and say คับkáp, which is why you'll often hear "khap" and see it spelled that way in messages. Both are the same word; "kráp" is the careful form and "káp" the everyday one.

Men use it after statements and questions alike:

• ขอบคุณครับkàwp-kun kráp: thank you
• ไปสนามบินครับbpai sà-nǎam-bin kráp: to the airport, please
• เท่าไหร่ครับtâo-rài kráp: how much is it?

The word started out as ขอรับkǎw-ráp, literally "I receive (your words)". According to the Office of the Royal Society, which publishes the official Thai dictionary, ครับkráp is a worn-down form of it; you still hear ขอรับkǎw-ráp in historical dramas. Two related forms you'll meet today: ครับผมkráp-pǒm, an extra-polite, eager "yes, sir" from waiters and staff, and ฮะhá, a softer, casual version men and boys use with family and people they know well.

Ka (ค่ะkâ and คะká): for women

Women have two forms, and the difference is the tone:

• ค่ะkâ (falling tone) after statements, answers, greetings and thanks: ขอบคุณค่ะkàwp-kun kâ (thank you), ได้ค่ะdâi kâ (sure, no problem).
• คะká (high tone) after questions: เท่าไหร่คะtâo-rài ká (how much is it?), ห้องน้ำอยู่ที่ไหนคะhâwng-náam yùu tîi-nǎi ká (where's the bathroom?).
• คะká also after นะná, even in statements: ขอบคุณนะคะkàwp-kun ná-ká (thanks so much).
• คะká when you call someone: น้องคะnáwng ká is how a woman calls a young waiter over (a man says น้องครับnáwng kráp).

Think of ค่ะkâ as a full stop and คะká as a question mark. On its own, ค่ะkâ means "yes" or "I see" (listen to any Thai woman on the phone), and a stretched, cheerful ค่าkâa is common in shops and in chat messages.

Why Thais use them

A bare Thai sentence can sound blunt. ไปสนามบินbpai sà-nǎam-bin on its own is like saying "Airport." to a driver; with ครับkráp or ค่ะkâ it becomes a polite request. The particles do the work that "please", "sir" and a friendly tone of voice do in English.

They also show respect in a culture that pays attention to age and status. You'll hear more of them towards elders, teachers, customers and officials, and fewer between friends. For a foreigner, using them is one of the quickest ways to come across as considerate, and Thais notice when you do.

When to use them and when to drop them

Use them:

• with strangers, shop staff, drivers and officials
• with anyone older than you: your partner's parents, a teacher, your landlord
• in greetings, thanks and apologies: สวัสดีsà-wàt-dii, ขอบคุณkàwp-kun and ขอโทษkǎw-tôot nearly always come with a particle
• when you ask for something: เช็คบิลด้วยchék-bin dûay (the bill, please) plus your particle
• on the phone, at work and in polite messages

Drop them, or use fewer:

• with close friends your own age, where a particle in every sentence sounds stiff
• in quick replies among people you know: ใช่châi (yes), ไม่mâi (no), โอเคoo-kee (okay)
• in exclamations and comments to yourself: อร่อยมากà-ràwy mâak (so good!), ร้อนráwn (hot!)
• in set expressions like ไม่เป็นไรmâi bpen rai (no worries) among friends
• with small children, where adults often switch to the warmer จ้ะjâ

When in doubt, add it. Being a little too polite is a much smaller problem than sounding curt.

Na krap, na ka, ja and friends

Polite particles often team up with other particles. The ones you'll hear every day:

• นะná softens a sentence: "okay?", "you know", "please". It comes first, then the polite particle: ไปก่อนนะbpai gàwn ná (I'm off now) becomes นะครับná-kráp for men and นะคะná-ká for women. Women use the high-tone คะká after นะná; writing it with the falling-tone spelling is a common mistake, even among Thais online.
• จ้ะjâ and จ้าjâa are warm and friendly, used mostly by women and by older people talking to younger ones. A street-food auntie might answer your order with ได้จ้ะdâi jâ (sure, dear); จ้าjâa is a cheerful "okay!" in chats. In questions it becomes จ๊ะjá.
• ครับผมkráp-pǒm and ฮะhá: the extra-polite and the casual male forms above.
• In messages you'll see playful spellings: คับkáp, ค่าkâa, คร้าบkráap (a drawn-out, cheerful krap) and the cute งับngáp.
• Regional speech has its own: in Chiang Mai you'll hear the Northern เจ้าjâo (yes, polite, used especially by women), and in Isan เด้อdôe does the job of นะná.

Particles and gender identity

The particle follows the gender you present as, and Thai speakers are used to that. Trans women generally use ค่ะkâ and คะká, and many trans men use ครับkráp. Some gay men use the female particles, playfully or as part of who they are, and some masculine women (often called ทอมtawm, "tom") use ครับkráp. People who'd rather not pick a side often lean on neutral words: the pronoun เราrao (I, we) and softeners like นะná.

For learners the rule is simple: use the particle that matches how you want to be seen, and follow other people's lead for them. The respectful modern word for a trans woman is ผู้หญิงข้ามเพศpûu-yǐng kâam-pêet. In our app you choose your particle once, and every phrase and your word for "I" (ผมpǒm for men, ฉันchǎn for women) adapt to it.

Common mistakes

1. Men saying "sawadee ka". Visitors pick it up from hotel and shop staff, many of whom are women. From a man it sounds feminine and usually earns a smile. Men say สวัสดีครับsà-wàt-dii kráp.
2. Women using ค่ะkâ in questions. เท่าไหร่ค่ะtâo-rài kâ sounds like a statement with a strange ending; the question is เท่าไหร่คะtâo-rài ká.
3. Thinking "ka" means thank you. The famous "kapunka" is simply ขอบคุณค่ะkàwp-kun kâ, a woman's thank-you said fast. The particle adds politeness, not meaning.
4. Putting the particle anywhere but the end. It closes the sentence: ขอบคุณมากครับkàwp-kun mâak kráp (thank you very much).
5. Using it in every sentence with friends. Once you're on nickname terms, a particle in every line sounds formal, a bit like calling a friend "sir". Keep it for greetings, thanks and requests.
6. Saying ค่ะkâ with a rising, English-question voice. It falls, firmly, like the end of a sentence. A rising or high "ka" turns it into the question form.
7. Mixing the forms. Men don't say นะคะná-ká, and women don't say ครับkráp (unless that's their identity, as above).

Practise: hear both versions

Every phrase below is shown for men and for women. Play the male and the female audio and listen to the ending change: ครับkráp after everything for men; ค่ะkâ or คะká for women, depending on whether it's a question. Then say each one out loud with your own particle. Our free course teaches the particles in its very first unit, "Hello, Thailand", and the speech trainer checks your tones as you say them.