thaiconv is a command line tool for converting text coding for Thai.

If you have read my Thai email guide then you will know that sending and receiving email in Thai can be beset with problems. To help you, thaiconv will determine the coding of a text file and convert it to a coding that you can read.

People on Un*x systems will be using something called iconv. I didn't know about iconv until after several versions of thaiconv, however, thaiconv has features that iconv doesn't have. I have created thaiconv to painlessly convert between Thai codings whereas iconv is a general tool.


thaiconv standard features include:

  1. Conversion of TIS-620, UTF-8, HTML Unicode and cross coded UTF-8. See Codings for an explanation
  2. Analysis mode to try to guess the coding of an input file
  3. Small command line executable
  4. Used in Sontana, my Thai text editor

thaiconv assumes that the text file you want to process is in Thai of some form. It's not suitable for processing other languages although it is OK if there are Roman letters in the file (i.e. no accents).

Changes in Version 1.7

Changes in Version 1.6

Improved guessing for the text coding.

Changes in Version 1.5


File Platform Version
thaiconv-1_6-amiga.lha AmigaOS 3, AmigaOS 4 and MorphOS 1.6
thaiconv-1_7-ARM.tar.bz2 Linux ARM (Zaurus) 1.7
thaiconv-1_7-PPC.tar.bz2 Linux PPC 1.7
thaiconv-1_7-mac.tar.bz2 MacOS X 1.7
thaiconv-1_5-x86.tar.bz2 Linux x86 1.5 Windows 1.5

Linux and Windows binaries are statically linked. The Mac binary is univeral (PPC and x86). If the idea of typing a command into a shell sounds too technical for you, then use Sontana instead.


Input Parameter Explanation

Usage: thaiconv [-h] [-s] [-sq] [-in X] [-out Y] [-noent] [-bom] -r input-filename -w output-filename
Display useful help information.
Scan input file and report on type.
Scan quick: same as above but only output a number according to the coding.
-in informat
Define input format. Optional, default = use scan to determine. Input and output formats are represented as numbers on the command line. See the help information for details.
-out outformat
Define output format. Optional, default = 0 (TIS-620).
-r input-filename
Use input-filename as input file. Required.
-w output-filename
Use output-filename as output file. If the output filename is not specified then output will go to the console (stdout).
Do not convert HTML numeric entities in TIS-620 or UTF-8 modes
Write a BOM at the start of Unicode files


Using thaiconv is straightforward, use -h to get comprehensive help information:

Work:Dev/ThaiConv:> thaiconv -h
thaiconv: Thai text transcoding tool. Version 1.7, Build 15122013.
Usage: thaiconv [-h] [-s] [-sq] [-in X] [-out Y] [-noent] [-bom] -r infilename [-w outfilename]

Convert plain text file encoding for Thai to another encoding.
 -s      scan file to determine type
 -sq     scan quiet - as above but only output the input file mode number
 -in     input format, see list below
 -out    output format, see list below
 -r      filename to read (required)
 -w      filename to write (default = stdout)
 -noent  don't convert HTML entities when reading
 -bom    write BOM when writing Unicode
 -h      this help
Input/Output Formats:
0 = TIS-620
1 = UTF-8 Thai
2 = HTML
3 = UTF-8 Latin 1 (cross coded Thai)
If the input format is not specified then it will be determined
automatically. If the result is not obvious TIS-620 will be assumed.
Use scan mode to find automatic result.
Output format defaults to TIS-620 unless specified.

For extended information please see

To convert a file from UTF-8 to TIS-620

Work:Dev/ThaiConv:> thaiconv -r utf8file.txt -out 0 > tis620file.txt

To convert a file from TIS-620 to UTF-8 :
Work:Dev/ThaiConv:> thaiconv -r tis620file.txt -out 1 > utf8file.txt

To convert a file from HTML Unicode to TIS-620:
Work:Dev/ThaiConv:> thaiconv -r htmlfile.txt -out 0 > tis620file.txt

To get thaiconv to tell you about the text file's coding:

Work:Dev/ThaiConv:> thaiconv -s -r testfile.txt
thaiconv Scan Report

12      plain ASCII characters.
0       extended ASCII characters.
17      HTML Unicode entities in Thai range.
29      Total characters.

File is probably Thai HTML Unicode

If you want to use thaiconv in a script and just want to know what coding the file is without parsing a lot of output:

Work:Dev/ThaiConv:> thaiconv -sq -r testfile.txt


The following table lists formats understood by thaiconv.

Standard 7 bit ASCII All alphabetical, numeric and punctuation characters used in standard ASCII. No accents, umlauts, ulls, fancy punctuation or graphics.
TIS-620 Thai characters are stored in the upper half of ASCII, i.e. using characters represented using 8 bit ASCII; thus allowing ASCII and Thai to co-exist.
UTF-8 (Thai range) The Unicode standard, specifically the section on Thai characters (0xE00 - 0xE7F).
HTML Unicode (Thai range) Unicode as represented in HTML: An entity of the form &#NNNN; or &#xHHHH; where NNNN is a decimal number and HHHH is a hexadecimal number.
Cross coded UTF-8 TIS-620 that has been converted to UTF-8 Latin1 (0xA0-0xF0). For example, the Thai character that has the value 160 in TIS-620 may have the Latin representation é, this character gets converted to the Unicode for é. This mode is likely to be converted correctly only if the cross coding and decoding occur in the same locality.