ចន្ទគតិខ្មែរ - Khmer Lunar Date & Calendar

The Khmer Lunar Date Converter takes an ordinary Gregorian date and shows the matching date in the traditional Khmer calendar, known as Chhankitek (ចន្ទគតិ). For any day you choose, it gives the lunar day and moon phase, the lunar month, the animal year, the sak, and the Buddhist Era year, written out in the formal Khmer style used on invitations and announcements. It also flags Buddhist holy days (ថ្ងៃសីល) and shows a holiday label when one falls on that date.

Families use the lunar calendar to plan merit-making, weddings and memorial ceremonies, and festivals such as Pchum Ben and the Water Festival follow lunar dates, so their Gregorian dates move every year.

How to use the tool

1. In បំលែងកាលបរិច្ឆេទ (Converter) mode, pick a day in ជ្រើសរើសថ្ងៃខែឆ្នាំសុរិយគតិ (Select Gregorian Date). Use the arrow buttons to step one day back or forward, or ថ្ងៃនេះ (Today) to return to the current date.
2. Read the result card. The large heading is the full lunar date, with the matching Gregorian date underneath.
3. Check the four boxes: ពុទ្ធសករាជ (B.E.), ខែចន្ទគតិ (Lunar Month), which also says whether it is a leap month, ឆ្នាំសត្វ (Zodiac Animal) and ស័ក (Era Sak).
4. Press ចម្លងកាលបរិច្ឆេទផ្លូវការ to copy the formal date text, ready to paste into a letter or invitation.
5. Switch to ប្រតិទិនប្រចាំខែ (Calendar Grid) to see a whole month. Each square shows the solar day and lunar day; sil days are tinted and marked with a dot.

How the Khmer lunar calendar works

Waxing and waning days

Each lunar month is split into two halves. During the waxing moon (កើត) days are counted from 1 to 15, ending at full moon. During the waning moon (រោច) counting restarts at 1 and runs to 14 or 15, depending on whether the month has 29 or 30 days. A date is therefore written as, for example, ៨រោច, "the 8th waning day".

Months, leap months and leap days

A year normally has 12 lunar months, about 11 days shorter than a solar year. To keep pace, some years double the month of Asath into បឋមាសាឍ and ទុតិយាសាឍ, and others gain an extra day. The tool applies these rules and labels a leap month Adhikamasa (Leap).

Animal year, sak and Buddhist Era

• The animal year follows the 12-animal cycle (ជូត, ឆ្លូវ, ខាល …) and changes at Khmer New Year in mid-April, not on 1 January.
• The sak is a separate 10-year cycle (ឯកស័ក to សំរឹទ្ធិស័ក) that also turns over at Khmer New Year.
• The Buddhist Era year changes after Visak Bochea, the full moon of ពិសាខ. Before that day the B.E. year is the Gregorian year plus 543; after it, plus 544.

Worked example

Selecting 4 October 2026 gives:

ថ្ងៃអាទិត្យ ៨រោច ខែភទ្របទ ឆ្នាំមមី អដ្ឋស័ក ពុទ្ធសករាជ ២៥៧០

That is Sunday, the 8th waning day of Photrobot, Year of the Horse, Atthasak, B.E. 2570 (2026 + 544, since Visak Bochea has passed). Seven days later, 11 October is ១៥រោច ខែភទ្របទ, Pchum Ben day, matching the official 2026 Pchum Ben holiday of 10–12 October.

Sil days

The tool marks four sil days in each lunar month: the 8th and 15th waxing days, the 8th waning day, and the last day of the month (14th or 15th waning). The 4 October example is therefore a sil day.

Accuracy and limits

Dates are calculated in your browser by an open-source Chhankitek library, supported from 1900 onwards; nothing is uploaded. The holiday label comes from the library's built-in list; Cambodia's public holidays are set each year by sub-decree and can change, so confirm the official announcement before planning time off.