Thai Buddhist Era Year Converter
Convert a Thai Buddhist or Gregorian year with the modern +543 convention and explicit labels across the BCE boundary.
Private in this browser: entered years and results are not added to the URL, saved, or sent as conversion data.
2569 BE
Thai digits: ๒๕๖๙
- Entered
- 2026 CE
- Formula
- Thai Buddhist proleptic year = ISO proleptic year + 543
- Boundary
- Modern Thai Buddhist Era +543 year convention.
Era-safe BCE and 25-row batch modes
Era-safe mode labels BCE and Before BE explicitly. Batch rows may carry their own era label; the default era applies only to an unmarked row.
This is exact proleptic arithmetic. Civil year zero stays internal and is never displayed.
Up to 25 rows and 512 Unicode characters. Explicit labels can mix CE, BCE, BE, and Before BE.
Modern Thai Buddhist Era uses a 543-year shift
This converter follows the modern Thai Buddhist chronology relationship documented by Oracle and implemented by OpenJDK: the Thai Buddhist proleptic year equals the ISO proleptic year plus 543. That makes 2026 CE equal to 2569 BE and 1 CE equal to 544 BE.
The page is a year converter. It does not promise a complete Buddhist calendar conversion, regional +544 rules, Thai lunar dates, holidays, timezones, or historical New Year cutovers.
Why era-safe mode avoids year zero
CE/BCE and BE/Before BE are year-of-era labels, so neither civil display has a year zero. The calculation uses an internal proleptic year: ISO proleptic 0 is displayed as 1 BCE. On the Thai side, proleptic 0 is displayed as 1 Before BE.
This produces exact boundary pairs: 1 BCE is 543 BE, 543 BCE is 1 BE, and 544 BCE is 1 Before BE. Entering 1 BE returns 543 BCE. These are proleptic arithmetic results, not claims that a modern Thai civil or historical regional calendar used those labels at the time.
Convert Thai-document years in a bounded batch
Batch mode accepts up to 25 lines and 512 Unicode characters. A row may use Western digits, Thai digits, CE, AD, BCE, BC, BE, B.E., พ.ศ., or Before BE. An explicit row label controls that row; the selected default applies only when a row has no label.
Rows remain in their original order, including duplicates. One invalid row gets its own error and does not erase valid rows. Copy all produces a visible-order TSV receipt. The page never silently truncates a longer paste.
Strict input and privacy boundaries
Use one positive whole year per item. Signs, decimals, exponents, mixed Western and Thai digits, conflicting single-input labels, unknown eras, and extra numbers are rejected. The supported range follows the proleptic ISO Year limits and uses integer arithmetic throughout.
All conversion happens in page memory. The tool does not put entered or derived years in query parameters, hashes, browser storage, cookies, application network requests, analytics fields, or structured data. Copy writes only the receipt you select and never reads the clipboard.
Frequently asked questions
How do I convert a Gregorian year to Thai Buddhist Era?
For a CE year under the modern Thai convention, add 543. For example, 2026 CE becomes 2569 BE. This tool uses exact proleptic-year arithmetic so the same rule remains explicit near era boundaries.
How do I convert Thai Buddhist Era to CE?
Subtract 543 from the Thai Buddhist proleptic year. Modern years such as 2569 BE become 2026 CE. A low BE year can cross into BCE, so era-safe mode labels that result instead of showing year zero or a negative CE number.
Can I enter Thai digits or พ.ศ.?
Yes. Enter one year with Western digits or Thai digits, and optionally use BE, B.E., or พ.ศ. as the Thai Buddhist Era label. The batch mode keeps up to 25 rows in order.
Why is there a Before BE era?
Before BE is the era-safe label for a Thai Buddhist proleptic year below BE 1. It is an arithmetic boundary label, not a claim about historical civil-calendar usage.
Does this convert complete Thai dates or regional Buddhist calendars?
No. It converts year numbers under the modern Thai +543 convention. It does not convert month/day dates, lunar calendars, holidays, historical New Year cutovers, or regional +544 conventions.
Are the years I enter stored or uploaded?
No. Conversion runs in this browser. Entered years and results are not placed in the URL, browser storage, application requests, structured data, or analytics.