How do I find my Thai zodiac sign (rasi koet)?

Enter your date of birth, and your time if you know it. The tool computes where the Sun stood in the sidereal zodiac used in Thailand. In practice each Thai sign starts around the 13th to 17th of the month: Mesha (Aries) around 13 or 14 April, Phruetsaphon (Taurus) around 15 May, and so on.

Why is my Thai sign different from my Western sign?

Western astrology follows the seasons (tropical zodiac) while Thai astrology follows the stars (sidereal zodiac). Because of the precession of the equinoxes they are now about 24° apart, or about 24 days. If you were born between roughly the 15th and the 20th of the month both signs match; otherwise your Thai sign is usually the one before your Western sign.

I was born on a sign change day. What is my sign?

Near a boundary, the time of birth decides. Add your birth time and the tool compares it with the exact moment the Sun changed sign that year. It also tells you when the fixed table used by Thai almanacs gives another sign, since that table keeps the same dates every year while the real moment shifts by about a day.

What is a ruling planet (dao chao ruean)?

It is the planet that governs the sign in Thai astrology: Mars for Aries and Scorpio, Venus for Taurus and Libra, Mercury for Gemini and Virgo, the Moon for Cancer, the Sun for Leo, Jupiter for Sagittarius and Pisces, Saturn for Capricorn, Rahu or Saturn for Aquarius. Each planet has a number (1 to 8) used in Thai charts.

What does Songkran have to do with the zodiac?

Songkran comes from the Sanskrit sankranti, the Sun's passage from one sign to the next. Maha Songkran, the great crossing, is its entry into Mesha, the first sign, around 13 or 14 April. It was the traditional Thai new year; the official holiday has since been fixed from 13 to 15 April.

What is the difference between Sun sign and ascendant (lakhana)?

The Sun sign (rasi koet) only depends on the date: it is where the Sun was. The ascendant (ลัคนา), central in Thai astrology, is the sign rising in the east at the minute of birth, so it needs the exact time and place. To find it, use our birth chart tool in sidereal mode.

Which signs get along according to tradition?

Signs of the same element (trine: fire, earth, air or water) are said to be in natural harmony, and signs two places apart (sextile) complement each other. The opposite sign both attracts and challenges. These are only symbolic guides: a relationship depends on the people in it.

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Thai zodiac sign

In Thailand the astrological year starts around 14 April, at Songkran, when the Sun enters sidereal Aries. That is why many Western Leos turn out to be Cancer in Thai astrology. Enter your date of birth: the tool computes the Sun's real position, shows the shift on a double wheel and gives you your rasi, its ruling planet, color and gemstone.

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Enter your date of birth to discover your Thai sign and how it differs from your Western sign.

The 12 sign dates this year (2026)

Exact moment the Sun enters each sign, in the chosen time zone, compared with the Western zodiac and the fixed table of Thai almanacs. (Bangkok)

Sign	Entry (Thai, computed)	Published Thai table	Entry (Western)
Ariesราศีเมษ	14 Apr, 10:36	13 April	20 Mar, 21:32
Taurusราศีพฤษภ	15 May, 07:26	15 May	20 Apr, 08:24
Geminiราศีเมถุน	15 Jun, 14:01	15 June	21 May, 07:23
Cancerราศีกรกฎ	17 Jul, 00:52	15 July	21 Jun, 15:15
Leoราศีสิงห์	17 Aug, 09:16	16 August	23 Jul, 02:08
Virgoราศีกันย์	17 Sept, 09:13	17 September	23 Aug, 09:17
Libraราศีตุลย์	17 Oct, 21:12	17 October	23 Sept, 07:05
Scorpioราศีพิจิก	16 Nov, 21:02	16 November	23 Oct, 16:36
Sagittariusราศีธนู	16 Dec, 11:42	16 December	22 Nov, 14:19
Capricornราศีมังกร	14 Jan, 16:17	15 January	22 Dec, 03:45
Aquariusราศีกุมภ์	13 Feb, 05:16	13 February	20 Jan, 08:35
Piscesราศีมีน	15 Mar, 02:08	15 March	18 Feb, 22:40

Why the two zodiacs drift apart

The Earth's axis wobbles slowly like a spinning top. The starting point of the Western zodiac (the March equinox) therefore slides against the stars, by about one degree every 72 years. Move the year to watch the gap grow and the Sun's entry into Mesha move later in the calendar.

Year2026

Gap (ayanamsa): Gap between the zodiacs: 24.2°
Sun enters Mesha: The Sun enters Mesha on 14 April

The two zodiacs matched around the year 293 (Lahiri formula). A full circle takes about 25,800 years.

Dates use the Gregorian calendar extended into the past; before 1582 people used other calendars, so the drift of Songkran is illustrative.

Based on Thai astrological tradition: these readings are symbolic guides for reflection and fun, and do not predict health, luck or money. For any health concern, please see a professional.

Thai zodiac sign

How it works

The zodiac is a belt of sky split into twelve signs of 30°, which the Sun crosses in a year. Western astrology starts the first sign (Aries) at the spring equinox, around 21 March: this is the tropical zodiac, tied to the seasons. Thai astrology, which grew out of Indian astrology, measures the signs against the fixed stars: this is the sidereal zodiac. The same moment can therefore fall in two different signs, and for most people it does.
The gap comes from the precession of the equinoxes. The Earth's axis slowly traces a cone, like a spinning top, so the equinox point slides back against the stars by about 50 arcseconds a year: one degree every 72 years and a full circle in roughly 26,000 years. With the formula used here, the two zodiacs lined up around the year 290; today the gap (the ayanamsa) is over 24°, which pushes every sign change back by about 24 days. That is why Thai signs change around the 13th to 17th of each month rather than the 20th to 23rd.
Everything is computed in your browser. The Sun's longitude comes from Jean Meeus's low precision formulas (Astronomical Algorithms), accurate to about a hundredth of a degree. We subtract the Lahiri ayanamsa, the official convention of Indian astrology, which the site's birth chart also uses. The tool then searches your birth year for the moment the Sun enters each sign, shown to the minute, in Bangkok time or the time zone you pick. The margin of error is a few minutes: for 2026 (BE 2569) the tool finds the Sun entering Mesha on 14 April at 10:36, while the official Maha Songkran announcement by the Brahmin astrologers of the Bureau of the Royal Household gives 10:34:35.
Thai astrologers traditionally calculate with the Suriyayatra (คัมภีร์สุริยยาตร), an old treatise whose results stay very close to the Lahiri calculation in our era (a few minutes apart for Songkran 2026). It sets the day of Maha Songkran, the Sun's entry into Mesha (Aries), around 13 or 14 April. In practice Thai media and almanacs publish fixed dates (Mesha from 13 April to 14 May, Phruetsaphon from 15 May to 14 June, and so on). The tool shows that table next to the exact calculation and tells you when the two disagree, which only happens within a day or two of a boundary: the table keeps the same dates every year, while the real moment shifts slightly from one year to the next.
Each sign has a ruling planet (ดาวเจ้าเรือน), numbered in the Thai way: 1 Sun, 2 Moon, 3 Mars, 4 Mercury, 5 Jupiter, 6 Venus, 7 Saturn, 8 Rahu. For Aquarius (Kum), Thai sources give either Rahu or Saturn, so we show both. The color is the one of the weekday that planet rules (the Thai day colors: red Sunday for the Sun, yellow Monday for the Moon and so on), and the stone is the planet's gem in the Nopparat, the nine jewels of Thai tradition. These links are beliefs, not established facts.
Sources: sign dates and ruling planets as published by KTC ("12 ราศี ตามโหราศาสตร์ไทย") and repeated by most Thai media; Thai Wikipedia for the day colors (สีประจำวัน) and the Nopparat (นพรัตน์); J. Meeus, Astronomical Algorithms, for the Sun; Lahiri ayanamsa (23°51' in 2000, 50.3" a year). Thai month names (เมษายน, พฤษภาคม and so on) were built from the sign names when Siam adopted the solar calendar under King Chulalongkorn (Rama V), decreed in 1888 and in use from 1889. Character traits and compatibility follow astrological tradition and are offered for reflection and fun.

These tools give general information. They do not replace the advice of a doctor or a qualified professional.

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Frequently asked questions

How do I find my Thai zodiac sign (rasi koet)?: Enter your date of birth, and your time if you know it. The tool computes where the Sun stood in the sidereal zodiac used in Thailand. In practice each Thai sign starts around the 13th to 17th of the month: Mesha (Aries) around 13 or 14 April, Phruetsaphon (Taurus) around 15 May, and so on.
Why is my Thai sign different from my Western sign?: Western astrology follows the seasons (tropical zodiac) while Thai astrology follows the stars (sidereal zodiac). Because of the precession of the equinoxes they are now about 24° apart, or about 24 days. If you were born between roughly the 15th and the 20th of the month both signs match; otherwise your Thai sign is usually the one before your Western sign.
I was born on a sign change day. What is my sign?: Near a boundary, the time of birth decides. Add your birth time and the tool compares it with the exact moment the Sun changed sign that year. It also tells you when the fixed table used by Thai almanacs gives another sign, since that table keeps the same dates every year while the real moment shifts by about a day.
What is a ruling planet (dao chao ruean)?: It is the planet that governs the sign in Thai astrology: Mars for Aries and Scorpio, Venus for Taurus and Libra, Mercury for Gemini and Virgo, the Moon for Cancer, the Sun for Leo, Jupiter for Sagittarius and Pisces, Saturn for Capricorn, Rahu or Saturn for Aquarius. Each planet has a number (1 to 8) used in Thai charts.
What does Songkran have to do with the zodiac?: Songkran comes from the Sanskrit sankranti, the Sun's passage from one sign to the next. Maha Songkran, the great crossing, is its entry into Mesha, the first sign, around 13 or 14 April. It was the traditional Thai new year; the official holiday has since been fixed from 13 to 15 April.
What is the difference between Sun sign and ascendant (lakhana)?: The Sun sign (rasi koet) only depends on the date: it is where the Sun was. The ascendant (ลัคนา), central in Thai astrology, is the sign rising in the east at the minute of birth, so it needs the exact time and place. To find it, use our birth chart tool in sidereal mode.
Which signs get along according to tradition?: Signs of the same element (trine: fire, earth, air or water) are said to be in natural harmony, and signs two places apart (sextile) complement each other. The opposite sign both attracts and challenges. These are only symbolic guides: a relationship depends on the people in it.

The 12 sign dates this year (2026)

Why the two zodiacs drift apart

How it works

Frequently asked questions

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