Thai Numbers 1-20: Counting Past Ten (Audio + Tone Marks)

Counting to twenty in Thai is almost entirely regular: learn the ten root words and two small twists and you have the whole range. One to ten are หนึ่ง (nʉ̀ng), สอง (sɔ̌ɔng), สาม (sǎam), สี่ (sìi), ห้า (hâa), หก (hòk), เจ็ด (jèt), แปด (bpɛ̀ɛt), เก้า (gâo), สิบ (sìp). From eleven you simply say สิบ ("ten") and bolt the next digit on — สิบสอง (sìp-sɔ̌ɔng) is 12, สิบห้า (sìp-hâa) is 15 — until you reach twenty, which has its own word, ยี่สิบ (yîi-sìp).

Numbers do not change for the speaker, so a man and a woman count identically; the gender particle only appears when you wrap a number in a sentence — "I'd like two, please" is ขอสองอันครับ (khɔ̌ɔ sɔ̌ɔng an khráp) for a man and ขอสองอันค่ะ (khɔ̌ɔ sɔ̌ɔng an khâ) for a woman. If you are still finding your feet with the script and tone marks, it is worth reading this alongside your first words of Thai.

The ten roots (1–10)

Everything rests on these ten. Here they are with the tone marked on each:

• หนึ่ง (nʉ̀ng) — 1, low tone
• สอง (sɔ̌ɔng) — 2, rising tone
• สาม (sǎam) — 3, rising tone
• สี่ (sìi) — 4, low tone
• ห้า (hâa) — 5, falling tone
• หก (hòk) — 6, low tone
• เจ็ด (jèt) — 7, low tone
• แปด (bpɛ̀ɛt) — 8, low tone
• เก้า (gâo) — 9, falling tone
• สิบ (sìp) — 10, low tone

Three of these carry a tone that English speakers habitually flatten. ห้า (hâa, 5) falls, เก้า (gâo, 9) falls, and สอง/สาม (2 and 3) both rise — say them on a lazy flat pitch and a Thai listener may hear nothing at all. The Paiboon diacritics printed above every flashcard show you exactly where the pitch should move; if the marks themselves are new to you, the guide to Paiboon vs RTGS tone marks explains what each one means.

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11 to 20: สิบ plus the pattern (and two curveballs)

From eleven onward the system is beautifully lazy. Take สิบ (sìp, 10) and add the ones digit: สิบสอง (sìp-sɔ̌ɔng) 12, สิบสาม (sìp-sǎam) 13, สิบสี่ (sìp-sìi) 14, and so on up to สิบเก้า (sìp-gâo) 19. There is no "and," no change of word order — just ten-two, ten-three, ten-four.

Two numbers break the mould, and they are the two you will say most often:

• 11 is สิบเอ็ด (sìp-èt), not สิบหนึ่ง. When "one" lands at the end of a compound number it switches from หนึ่ง to เอ็ด (èt). This is not optional and it is not regional — it is simply how the number is said, and it comes back for 21 (ยี่สิบเอ็ด), 31, 101, and every "…-one" after.
• 20 is ยี่สิบ (yîi-sìp), not สองสิบ. ยี่ (yîi) is an old word for "two" that has almost vanished from the language except here; twenty kept it. Thirty onward is regular again — สามสิบ (sǎam-sìp) 30, สี่สิบ (sìi-sìp) 40 — so ยี่สิบ is the one survivor you simply memorise.

Get those two right and the gap between 10 and 100 holds no surprises.

Counting real things: the classifier

In the wild, a number rarely travels alone — Thai slots a classifier between the noun and the number. The shape is noun + number + classifier: กาแฟสองแก้ว (gaa-fɛɛ sɔ̌ɔng gɛ̂ɛw), "two coffees," literally "coffee two glasses." Bottles take ขวด (khùat), flat things take ใบ (bai), and the all-purpose fallback for objects is อัน (an). You do not need to master classifiers to be understood — pointing and saying สอง works — but hearing สองขวด instead of สอง is what makes an order sound native. The same numbers power money and market haggling, which is why they sit at the heart of our in-app "Numbers, Money & Counting" deck, where ยี่สิบ ("twenty") is drilled until its falling–low shape — yîi then sìp — comes without thinking. Numbers also pair naturally with the rest of the everyday core — the days of the week and the colors are built the same modular way.

The mistakes to skip

The slip I see most from beginners is saying สิบหนึ่ง for 11. It is a perfectly logical guess — ten plus one — but it is wrong; the ones-place "one" is always เอ็ด, so it is สิบเอ็ด. The second is regularising twenty to สองสิบ, which sounds to a Thai ear roughly the way "two-ty" would to yours. The third is tonal: letting ห้า (5) and เก้า (9) sag flat instead of falling. Thai has plenty of near-homophones separated only by tone, and a flat ห้า can drift toward ฮา (haa, "to laugh"), so the pitch is doing real work.

One habit makes all of this stick faster: count things you can already see. Tuk-tuks at the lights, floors in the lift, baht on a price tag — run the number in Thai before you reach for English. Twenty words, two exceptions, and a week of counting what is in front of you, and 1–20 stops being vocabulary and becomes reflex. When you are ready for more, slot these in beside the broader set of essential Thai phrases and run the deck above in both directions.