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System.Text.Encoding class

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This article provides supplementary remarks to the reference documentation for this API.

The Encoding class represents a character encoding.

Encoding is the process of transforming a set of Unicode characters into a sequence of bytes. In contrast, decoding is the process of transforming a sequence of encoded bytes into a set of Unicode characters. For information about the Unicode Transformation Formats (UTFs) and other encodings supported by Encoding, see Character Encoding in .NET.

Encoding is intended to operate on Unicode characters instead of arbitrary binary data, such as byte arrays. If you must encode arbitrary binary data into text, you should use a protocol such as uuencode, which is implemented by methods such as Convert.ToBase64CharArray.

.NET provides the following implementations of the Encoding class to support current Unicode encodings and other encodings:

  • ASCIIEncoding encodes Unicode characters as single 7-bit ASCII characters. This encoding only supports character values between U+0000 and U+007F. Code page 20127. Also available through the ASCII property.

  • UTF7Encoding encodes Unicode characters using the UTF-7 encoding. This encoding supports all Unicode character values. Code page 65000. Also available through the UTF7 property.

  • UTF8Encoding encodes Unicode characters using the UTF-8 encoding. This encoding supports all Unicode character values. Code page 65001. Also available through the UTF8 property.

  • UnicodeEncoding encodes Unicode characters using the UTF-16 encoding. Both little endian and big endian byte orders are supported. Also available through the Unicode property and the BigEndianUnicode property.

  • UTF32Encoding encodes Unicode characters using the UTF-32 encoding. Both little endian (code page 12000) and big endian (code page 12001) byte orders are supported. Also available through the UTF32 property.

The Encoding class is primarily intended to convert between different encodings and Unicode. Often one of the derived Unicode classes is the correct choice for your app.

Use the GetEncoding method to obtain other encodings, and call the GetEncodings method to get a list of all encodings.

List of encodings

The following table lists the encodings supported by .NET. It lists each encoding's code page number and the values of the encoding's EncodingInfo.Name and EncodingInfo.DisplayName properties. A check mark in the .NET Framework support, .NET Core support, or .NET 5 and later support column indicates that the code page is natively supported by that .NET implementation, regardless of the underlying platform. For .NET Framework, the availability of other encodings listed in the table depends on the operating system. For .NET Core and .NET 5 and later versions, other encodings are available by using the System.Text.CodePagesEncodingProvider class or by deriving from the System.Text.EncodingProvider class.

Note

Code pages whose EncodingInfo.Name property corresponds to an international standard do not necessarily comply in full with that standard.

Code page Name Display name .NET Framework support .NET Core support .NET 5 and later support
37 IBM037 IBM EBCDIC (US-Canada)
437 IBM437 OEM United States
500 IBM500 IBM EBCDIC (International)
708 ASMO-708 Arabic (ASMO 708)
720 DOS-720 Arabic (DOS)
737 ibm737 Greek (DOS)
775 ibm775 Baltic (DOS)
850 ibm850 Western European (DOS)
852 ibm852 Central European (DOS)
855 IBM855 OEM Cyrillic
857 ibm857 Turkish (DOS)
858 IBM00858 OEM Multilingual Latin I
860 IBM860 Portuguese (DOS)
861 ibm861 Icelandic (DOS)
862 DOS-862 Hebrew (DOS)
863 IBM863 French Canadian (DOS)
864 IBM864 Arabic (864)
865 IBM865 Nordic (DOS)
866 cp866 Cyrillic (DOS)
869 ibm869 Greek, Modern (DOS)
870 IBM870 IBM EBCDIC (Multilingual Latin-2)
874 windows-874 Thai (Windows)
875 cp875 IBM EBCDIC (Greek Modern)
932 shift_jis Japanese (Shift-JIS)
936 gb2312 Chinese Simplified (GB2312) ✓
949 ks_c_5601-1987 Korean
950 big5 Chinese Traditional (Big5)
1026 IBM1026 IBM EBCDIC (Turkish Latin-5)
1047 IBM01047 IBM Latin-1
1140 IBM01140 IBM EBCDIC (US-Canada-Euro)
1141 IBM01141 IBM EBCDIC (Germany-Euro)
1142 IBM01142 IBM EBCDIC (Denmark-Norway-Euro)
1143 IBM01143 IBM EBCDIC (Finland-Sweden-Euro)
1144 IBM01144 IBM EBCDIC (Italy-Euro)
1145 IBM01145 IBM EBCDIC (Spain-Euro)
1146 IBM01146 IBM EBCDIC (UK-Euro)
1147 IBM01147 IBM EBCDIC (France-Euro)
1148 IBM01148 IBM EBCDIC (International-Euro)
1149 IBM01149 IBM EBCDIC (Icelandic-Euro)
1200 utf-16 Unicode ✓ ✓ ✓
1201 unicodeFFFE Unicode (Big endian) ✓ ✓ ✓
1250 windows-1250 Central European (Windows)
1251 windows-1251 Cyrillic (Windows)
1252 Windows-1252 Western European (Windows) ✓
1253 windows-1253 Greek (Windows)
1254 windows-1254 Turkish (Windows)
1255 windows-1255 Hebrew (Windows)
1256 windows-1256 Arabic (Windows)
1257 windows-1257 Baltic (Windows)
1258 windows-1258 Vietnamese (Windows)
1361 Johab Korean (Johab)
10000 macintosh Western European (Mac)
10001 x-mac-japanese Japanese (Mac)
10002 x-mac-chinesetrad Chinese Traditional (Mac)
10003 x-mac-korean Korean (Mac) ✓
10004 x-mac-arabic Arabic (Mac)
10005 x-mac-hebrew Hebrew (Mac)
10006 x-mac-greek Greek (Mac)
10007 x-mac-cyrillic Cyrillic (Mac)
10008 x-mac-chinesesimp Chinese Simplified (Mac) ✓
10010 x-mac-romanian Romanian (Mac)
10017 x-mac-ukrainian Ukrainian (Mac)
10021 x-mac-thai Thai (Mac)
10029 x-mac-ce Central European (Mac)
10079 x-mac-icelandic Icelandic (Mac)
10081 x-mac-turkish Turkish (Mac)
10082 x-mac-croatian Croatian (Mac)
12000 utf-32 Unicode (UTF-32) ✓ ✓ ✓
12001 utf-32BE Unicode (UTF-32 Big endian) ✓ ✓ ✓
20000 x-Chinese-CNS Chinese Traditional (CNS)
20001 x-cp20001 TCA Taiwan
20002 x-Chinese-Eten Chinese Traditional (Eten)
20003 x-cp20003 IBM5550 Taiwan
20004 x-cp20004 TeleText Taiwan
20005 x-cp20005 Wang Taiwan
20105 x-IA5 Western European (IA5)
20106 x-IA5-German German (IA5)
20107 x-IA5-Swedish Swedish (IA5)
20108 x-IA5-Norwegian Norwegian (IA5)
20127 us-ascii US-ASCII ✓ ✓ ✓
20261 x-cp20261 T.61
20269 x-cp20269 ISO-6937
20273 IBM273 IBM EBCDIC (Germany)
20277 IBM277 IBM EBCDIC (Denmark-Norway)
20278 IBM278 IBM EBCDIC (Finland-Sweden)
20280 IBM280 IBM EBCDIC (Italy)
20284 IBM284 IBM EBCDIC (Spain)
20285 IBM285 IBM EBCDIC (UK)
20290 IBM290 IBM EBCDIC (Japanese katakana)
20297 IBM297 IBM EBCDIC (France)
20420 IBM420 IBM EBCDIC (Arabic)
20423 IBM423 IBM EBCDIC (Greek)
20424 IBM424 IBM EBCDIC (Hebrew)
20833 x-EBCDIC-KoreanExtended IBM EBCDIC (Korean Extended)
20838 IBM-Thai IBM EBCDIC (Thai)
20866 koi8-r Cyrillic (KOI8-R)
20871 IBM871 IBM EBCDIC (Icelandic)
20880 IBM880 IBM EBCDIC (Cyrillic Russian)
20905 IBM905 IBM EBCDIC (Turkish)
20924 IBM00924 IBM Latin-1
20932 EUC-JP Japanese (JIS 0208-1990 and 0212-1990)
20936 x-cp20936 Chinese Simplified (GB2312-80) ✓
20949 x-cp20949 Korean Wansung ✓
21025 cp1025 IBM EBCDIC (Cyrillic Serbian-Bulgarian)
21866 koi8-u Cyrillic (KOI8-U)
28591 iso-8859-1 Western European (ISO) ✓ ✓ ✓
28592 iso-8859-2 Central European (ISO)
28593 iso-8859-3 Latin 3 (ISO)
28594 iso-8859-4 Baltic (ISO)
28595 iso-8859-5 Cyrillic (ISO)
28596 iso-8859-6 Arabic (ISO)
28597 iso-8859-7 Greek (ISO)
28598 iso-8859-8 Hebrew (ISO-Visual) ✓
28599 iso-8859-9 Turkish (ISO)
28603 iso-8859-13 Estonian (ISO)
28605 iso-8859-15 Latin 9 (ISO)
29001 x-Europa Europa
38598 iso-8859-8-i Hebrew (ISO-Logical) ✓
50220 iso-2022-jp Japanese (JIS) ✓
50221 csISO2022JP Japanese (JIS-Allow 1 byte Kana) ✓
50222 iso-2022-jp Japanese (JIS-Allow 1 byte Kana - SO/SI) ✓
50225 iso-2022-kr Korean (ISO) ✓
50227 x-cp50227 Chinese Simplified (ISO-2022) ✓
51932 euc-jp Japanese (EUC) ✓
51936 EUC-CN Chinese Simplified (EUC) ✓
51949 euc-kr Korean (EUC) ✓
52936 hz-gb-2312 Chinese Simplified (HZ) ✓
54936 GB18030 Chinese Simplified (GB18030) ✓
57002 x-iscii-de ISCII Devanagari ✓
57003 x-iscii-be ISCII Bengali ✓
57004 x-iscii-ta ISCII Tamil ✓
57005 x-iscii-te ISCII Telugu ✓
57006 x-iscii-as ISCII Assamese ✓
57007 x-iscii-or ISCII Oriya ✓
57008 x-iscii-ka ISCII Kannada ✓
57009 x-iscii-ma ISCII Malayalam ✓
57010 x-iscii-gu ISCII Gujarati ✓
57011 x-iscii-pa ISCII Punjabi ✓
65000 utf-7 Unicode (UTF-7) ✓ ✓
65001 utf-8 Unicode (UTF-8) ✓ ✓ ✓

The following example calls the GetEncoding(Int32) and GetEncoding(String) methods to get the Greek (Windows) code page encoding. It compares the Encoding objects returned by the method calls to show that they are equal, and then maps displays the Unicode code point and the corresponding code page value for each character in the Greek alphabet.

using System;
using System.Text;

public class Example
{
   public static void Main()
   {
      Encoding enc = Encoding.GetEncoding(1253);
      Encoding altEnc = Encoding.GetEncoding("windows-1253");
      Console.WriteLine("{0} = Code Page {1}: {2}", enc.EncodingName,
                        altEnc.CodePage, enc.Equals(altEnc));
      string greekAlphabet = "Α α Β β Γ γ Δ δ Ε ε Ζ ζ Η η " +
                             "Θ θ Ι ι Κ κ Λ λ Μ μ Ν ν Ξ ξ " +
                             "Ο ο Π π Ρ ρ Σ σ ς Τ τ Υ υ " +
                             "Φ φ Χ χ Ψ ψ Ω ω";
      Console.OutputEncoding = Encoding.UTF8;
      byte[] bytes = enc.GetBytes(greekAlphabet);
      Console.WriteLine("{0,-12} {1,20} {2,20:X2}", "Character",
                        "Unicode Code Point", "Code Page 1253");
      for (int ctr = 0; ctr < bytes.Length; ctr++) {
         if (greekAlphabet[ctr].Equals(' '))
            continue;

         Console.WriteLine("{0,-12} {1,20} {2,20:X2}", greekAlphabet[ctr],
                           GetCodePoint(greekAlphabet[ctr]), bytes[ctr]);
      }
   }

   private static string GetCodePoint(char ch)
   {
      string retVal = "u+";
      byte[] bytes = Encoding.Unicode.GetBytes(ch.ToString());
      for (int ctr = bytes.Length - 1; ctr >= 0; ctr--)
         retVal += bytes[ctr].ToString("X2");

      return retVal;
   }
}
// The example displays the following output:
//       Character      Unicode Code Point       Code Page 1253
//       Α                          u+0391                   C1
//       α                          u+03B1                   E1
//       Β                          u+0392                   C2
//       β                          u+03B2                   E2
//       Γ                          u+0393                   C3
//       γ                          u+03B3                   E3
//       Δ                          u+0394                   C4
//       δ                          u+03B4                   E4
//       Ε                          u+0395                   C5
//       ε                          u+03B5                   E5
//       Ζ                          u+0396                   C6
//       ζ                          u+03B6                   E6
//       Η                          u+0397                   C7
//       η                          u+03B7                   E7
//       Θ                          u+0398                   C8
//       θ                          u+03B8                   E8
//       Ι                          u+0399                   C9
//       ι                          u+03B9                   E9
//       Κ                          u+039A                   CA
//       κ                          u+03BA                   EA
//       Λ                          u+039B                   CB
//       λ                          u+03BB                   EB
//       Μ                          u+039C                   CC
//       μ                          u+03BC                   EC
//       Ν                          u+039D                   CD
//       ν                          u+03BD                   ED
//       Ξ                          u+039E                   CE
//       ξ                          u+03BE                   EE
//       Ο                          u+039F                   CF
//       ο                          u+03BF                   EF
//       Π                          u+03A0                   D0
//       π                          u+03C0                   F0
//       Ρ                          u+03A1                   D1
//       ρ                          u+03C1                   F1
//       Σ                          u+03A3                   D3
//       σ                          u+03C3                   F3
//       ς                          u+03C2                   F2
//       Τ                          u+03A4                   D4
//       τ                          u+03C4                   F4
//       Υ                          u+03A5                   D5
//       υ                          u+03C5                   F5
//       Φ                          u+03A6                   D6
//       φ                          u+03C6                   F6
//       Χ                          u+03A7                   D7
//       χ                          u+03C7                   F7
//       Ψ                          u+03A8                   D8
//       ψ                          u+03C8                   F8
//       Ω                          u+03A9                   D9
//       ω                          u+03C9                   F9

Imports System.Text

Module Example
   Public Sub Main()
      Dim enc As Encoding = Encoding.GetEncoding(1253)
      Dim altEnc As Encoding = Encoding.GetEncoding("windows-1253")
      Console.WriteLine("{0} = Code Page {1}: {2}", enc.EncodingName,
                        altEnc.CodePage, enc.Equals(altEnc))
      Dim greekAlphabet As String = "Α α Β β Γ γ Δ δ Ε ε Ζ ζ Η η " +
                                    "Θ θ Ι ι Κ κ Λ λ Μ μ Ν ν Ξ ξ " +
                                    "Ο ο Π π Ρ ρ Σ σ ς Τ τ Υ υ " +
                                    "Φ φ Χ χ Ψ ψ Ω ω"
      Console.OutputEncoding = Encoding.UTF8
      Dim bytes() As Byte = enc.GetBytes(greekAlphabet)
      Console.WriteLine("{0,-12} {1,20} {2,20:X2}", "Character",
                        "Unicode Code Point", "Code Page 1253")
      For ctr As Integer = 0 To bytes.Length - 1
         If greekAlphabet(ctr).Equals(" "c) Then Continue For

         Console.WriteLine("{0,-12} {1,20} {2,20:X2}", greekAlphabet(ctr),
                           GetCodePoint(greekAlphabet(ctr)), bytes(ctr))
      Next

   End Sub
   
   Private Function GetCodePoint(ch As String) As String
      Dim retVal As String = "u+"
      Dim bytes() As Byte = Encoding.Unicode.GetBytes(ch)
      For ctr As Integer = bytes.Length - 1 To 0 Step -1
         retVal += bytes(ctr).ToString("X2")
      Next
      Return retVal
   End Function
End Module
' The example displays the following output:
'    Character      Unicode Code Point       Code Page 1253
'    Α                          u+0391                   C1
'    α                          u+03B1                   E1
'    Β                          u+0392                   C2
'    β                          u+03B2                   E2
'    Γ                          u+0393                   C3
'    γ                          u+03B3                   E3
'    Δ                          u+0394                   C4
'    δ                          u+03B4                   E4
'    Ε                          u+0395                   C5
'    ε                          u+03B5                   E5
'    Ζ                          u+0396                   C6
'    ζ                          u+03B6                   E6
'    Η                          u+0397                   C7
'    η                          u+03B7                   E7
'    Θ                          u+0398                   C8
'    θ                          u+03B8                   E8
'    Ι                          u+0399                   C9
'    ι                          u+03B9                   E9
'    Κ                          u+039A                   CA
'    κ                          u+03BA                   EA
'    Λ                          u+039B                   CB
'    λ                          u+03BB                   EB
'    Μ                          u+039C                   CC
'    μ                          u+03BC                   EC
'    Ν                          u+039D                   CD
'    ν                          u+03BD                   ED
'    Ξ                          u+039E                   CE
'    ξ                          u+03BE                   EE
'    Ο                          u+039F                   CF
'    ο                          u+03BF                   EF
'    Π                          u+03A0                   D0
'    π                          u+03C0                   F0
'    Ρ                          u+03A1                   D1
'    ρ                          u+03C1                   F1
'    Σ                          u+03A3                   D3
'    σ                          u+03C3                   F3
'    ς                          u+03C2                   F2
'    Τ                          u+03A4                   D4
'    τ                          u+03C4                   F4
'    Υ                          u+03A5                   D5
'    υ                          u+03C5                   F5
'    Φ                          u+03A6                   D6
'    φ                          u+03C6                   F6
'    Χ                          u+03A7                   D7
'    χ                          u+03C7                   F7
'    Ψ                          u+03A8                   D8
'    ψ                          u+03C8                   F8
'    Ω                          u+03A9                   D9
'    ω                          u+03C9                   F9

If the data to be converted is available only in sequential blocks (such as data read from a stream) or if the amount of data is so large that it needs to be divided into smaller blocks, you should use the Decoder or the Encoder provided by the GetDecoder method or the GetEncoder method, respectively, of a derived class.

The UTF-16 and the UTF-32 encoders can use the big endian byte order (most significant byte first) or the little endian byte order (least significant byte first). For example, the Latin Capital Letter A (U+0041) is serialized as follows (in hexadecimal):

  • UTF-16 big endian byte order: 00 41
  • UTF-16 little endian byte order: 41 00
  • UTF-32 big endian byte order: 00 00 00 41
  • UTF-32 little endian byte order: 41 00 00 00

It is generally more efficient to store Unicode characters using the native byte order. For example, it is better to use the little endian byte order on little endian platforms, such as Intel computers.

The GetPreamble method retrieves an array of bytes that includes the byte order mark (BOM). If this byte array is prefixed to an encoded stream, it helps the decoder to identify the encoding format used.

For more information on byte order and the byte order mark, see The Unicode Standard at the Unicode home page.

Note that the encoding classes allow errors to:

  • Silently change to a "?" character.
  • Use a "best fit" character.
  • Change to an application-specific behavior through use of the EncoderFallback and DecoderFallback classes with the U+FFFD Unicode replacement character.

You should throw an exception on any data stream error. An app either uses a "throwonerror" flag when applicable or uses the EncoderExceptionFallback and DecoderExceptionFallback classes. Best fit fallback is often not recommended because it can cause data loss or confusion and is slower than simple character replacements. For ANSI encodings, the best fit behavior is the default.