Poya days and uposatha days for the year
This calendar lists the Poya days and other uposatha days of the year — the full-moon, new-moon and quarter-moon days on which many Theravada Buddhists keep the eight precepts, visit the temple and listen to the Dhamma. Choose Sri Lanka, Thailand, Myanmar or your own time zone and a year; it shows each observance day with the moment of the moon’s phase, names each Sri Lankan Poya (Duruthu, Navam, Medin … Unduvap, with an Adhi month when there is one) and tells you how long it is until the next one.
The dates are calculated from the Moon, so they work for any year from 1900 to 2100, and they are labelled as computed: official calendars are prepared by people, and they sometimes place a day differently.
How to use the Uposatha & Poya Days Calendar
- Enter the Year, or press This year.
- Pick Sri Lanka, Thailand, Myanmar or My time zone.
- Tick the moon phases you want to see under Show; untick all but Full moon for a plain Poya list.
- The box shows the next observance day; the table lists the whole year with the phase time in local time.
- Press Download CSV or Add to calendar (.ics) to keep the dates.
Uposatha & Poya Days Calendar features
Sri Lankan Poya names
Each full moon is named after its lunar month, including Adhi (extra) months such as Adhi Poson in 2026.
Four phases
Full moon, new moon and both quarter days, the traditional four uposatha days of the month.
Three countries
Dates are worked out in Sri Lankan, Thai or Myanmar time, or in your own time zone.
Vesak table
When Vesak falls in Sri Lanka, India, Thailand and Singapore, from the official holiday lists.
How the dates are worked out
The moon’s phases come from the same astronomy as the moon phase calculator, refined to the minute. A new-moon, quarter or full-moon uposatha is placed on the local calendar date of that phase.
For Sri Lanka’s full-moon Poya day the page uses the lunar day (tithi) instead: the Poya is the day on which the full-moon tithi, Purnima, begins, if it begins before 6 pm Sri Lanka time, and otherwise the next day. Purnima starts roughly a day before the exact full moon, which is why the Poya is often the day before the full moon in a diary. This rule reproduces every one of the 37 Poya days gazetted for 2025, 2026 and 2027. When Purnima begins within 45 minutes of 6 pm the row is marked as a close call.
The month names follow the lunar months of the South Asian calendar (the month ending at that full moon): Bak is Chaitra, Vesak is Vaishakha, Poson is Jyeshtha, and so on. A lunar month in which the Sun does not enter a new sign is an extra (adhi) month; in 2026 that is Adhi Poson, gazetted for 30 May.
Why calendars disagree by a day
In Thailand the Mahanikaya calendar follows a traditional arithmetical scheme, while the Dhammayut order follows astronomical calculation, so the two can keep a wan phra a day apart. Myanmar’s calendar also has its own rules, and Thai and Myanmar calendars add their extra month in different years from Sri Lanka, which is why Vesak fell on 1 May in Sri Lanka and India in 2026 but on 31 May in Thailand and Singapore. For a vow or a temple visit, follow your monastery or the official calendar.
| Phase | Sri Lanka | Thailand | Myanmar |
|---|---|---|---|
| Full moon | Poya | Wan Phra (15th waxing) | La Pyae |
| New moon | Amavaka | Wan Phra (14th or 15th waning) | La Kwe |
| Quarters | Atawaka | Wan Phra (8th waxing / waning) | 8th waxing / waning |
Uposatha & Poya Days Calendar FAQ
When is the next Poya day?
The box at the top shows it for the current year in Sri Lanka, with the number of days to go. Untick the other phases to see only Poya days.
What are the Poya days in 2026 in Sri Lanka?
Duruthu 3 January, Navam 1 February, Medin 2 March, Bak 1 April, Vesak 1 May, Adhi Poson 30 May, Poson 29 June, Esala 29 July, Nikini 27 August, Binara 26 September, Vap 25 October, Il 24 November and Unduvap 23 December.
When is Vesak in 2027?
Sri Lanka’s Vesak Poya is on 19 May 2027; India, Thailand and Singapore have announced 20 May 2027.
What is an uposatha day?
It is the Buddhist observance day on the full moon, the new moon and the two quarter moons. Lay followers often keep the eight precepts, and monks recite the Patimokkha on the full and new moons.
Why does my temple calendar show a different day?
Calendars use different traditional rules and time zones, and the Thai Mahanikaya and Dhammayut calendars can differ from each other by a day. The dates here are computed; follow your temple for practice.
Can I add the dates to my phone calendar?
Yes. Press Add to calendar (.ics) and open the file with your calendar app, or download the CSV for a spreadsheet.