ASCII（American Standard Code for Information Interchange，美国信息互换标准代码，ASCII）是基于拉丁字母的一套电脑编码系统。它主要用于显示现代英语和其他西欧语言。它是现今最通用的单字节编码系统，并等同于国际标准ISO/IEC 646。
ASCII码大致可以分作三部分组成。
第1部分：ASCII非打印控制字符
ASCII表上的数字0–31分配给了控制字符，用于控制像打印机等一些外围设备。例如，12代表换页/新页功能。此命令指示打印机跳到下一页的开头。当您查看或打印文档时这些字符不会显示出来（详参ASCII码表中0-31）
第2部分：ASCII打印字符
数字 32–126 分配给了能在键盘上找到的字符，当您查看或打印文档时这些字符将会显示出来。如数字49代表 字符’1’。（详参ASCII码表中32-127）
第3部分：扩展ASCII打印字符
扩展的ASCII字符满足了对更多字符的需求。扩展的ASCII包含ASCII中已有的128个字符（数字0–32显示在下图中），又增加了128个字符，总共是256个。即使有了这些更多的字符，许多语言还是包含无法压缩到256个字符中的符号。因此，出现了一些ASCII的变体来囊括地区性字符和符号。例如，许多软件程序把ASCII表（又称作ISO8859-1）用于北美、西欧、澳大利亚和非洲的语言。
| 2进制 | 10进制 | 16进制 | 缩写/字符 | 解释 |
| 00000000 | 0 | 00 | NUL(null) | 空字符 |
| 00000001 | 1 | 01 | SOH(start of headling) | 标题开始 |
| 00000010 | 2 | 02 | STX (start of text) | 正文开始 |
| 00000011 | 3 | 03 | ETX (end of text) | 正文结束 |
| 00000100 | 4 | 04 | EOT (end of transmission) | 传输结束 |
| 00000101 | 5 | 05 | ENQ (enquiry) | 请求 |
| 00000110 | 6 | 06 | ACK (acknowledge) | 收到通知 |
| 00000111 | 7 | 07 | BEL (bell) | 响铃 |
| 00001000 | 8 | 08 | BS (backspace) | 退格 |
| 00001001 | 9 | 09 | HT (horizontal tab) | 水平制表符 |
| 00001010 | 10 | 0A | LF (NL line feed, new line) | 换行符 |
| 00001011 | 11 | 0B | VT (vertical tab) | 垂直制表符 |
| 00001100 | 12 | 0C | FF (NP form feed, new page) | 换页键 |
| 00001101 | 13 | 0D | CR (carriage return) | 回车键 |
| 00001110 | 14 | 0E | SO (shift out) | 不用切换 |
| 00001111 | 15 | 0F | SI (shift in) | 启用切换 |
| 00010000 | 16 | 10 | DLE (data link escape) | 数据链路转义 |
| 00010001 | 17 | 11 | DC1 (device control 1) | 设备控制1 |
| 00010010 | 18 | 12 | DC2 (device control 2) | 设备控制2 |
| 00010011 | 19 | 13 | DC3 (device control 3) | 设备控制3 |
| 00010100 | 20 | 14 | DC4 (device control 4) | 设备控制4 |
| 00010101 | 21 | 15 | NAK (negative acknowledge) | 拒绝接收 |
| 00010110 | 22 | 16 | SYN (synchronous idle) | 同步空闲 |
| 00010111 | 23 | 17 | ETB (end of trans. block) | 传输块结束 |
| 00011000 | 24 | 18 | CAN (cancel) | 取消 |
| 00011001 | 25 | 19 | EM (end of medium) | 介质中断 |
| 00011010 | 26 | 1A | SUB (substitute) | 替补 |
| 00011011 | 27 | 1B | ESC (escape) | 溢出 |
| 00011100 | 28 | 1C | FS (file separator) | 文件分割符 |
| 00011101 | 29 | 1D | GS (group separator) | 分组符 |
| 00011110 | 30 | 1E | RS (record separator) | 记录分离符 |
| 00011111 | 31 | 1F | US (unit separator) | 单元分隔符 |
| 00100000 | 32 | 20 | (space) | 空格 |
| 00100001 | 33 | 21 | ! | |
| 00100010 | 34 | 22 | “ | |
| 00100011 | 35 | 23 | # | |
| 00100100 | 36 | 24 | $ | |
| 00100101 | 37 | 25 | % | |
| 00100110 | 38 | 26 | & | |
| 00100111 | 39 | 27 | ‘ | |
| 00101000 | 40 | 28 | ( | |
| 00101001 | 41 | 29 | ) | |
| 00101010 | 42 | 2A | * | |
| 00101011 | 43 | 2B | + | |
| 00101100 | 44 | 2C | , | |
| 00101101 | 45 | 2D | – | |
| 00101110 | 46 | 2E | . | |
| 00101111 | 47 | 2F | / | |
| 00110000 | 48 | 30 | 0 | |
| 00110001 | 49 | 31 | 1 | |
| 00110010 | 50 | 32 | 2 | |
| 00110011 | 51 | 33 | 3 | |
| 00110100 | 52 | 34 | 4 | |
| 00110101 | 53 | 35 | 5 | |
| 00110110 | 54 | 36 | 6 | |
| 00110111 | 55 | 37 | 7 | |
| 00111000 | 56 | 38 | 8 | |
| 00111001 | 57 | 39 | 9 | |
| 00111010 | 58 | 3A | : | |
| 00111011 | 59 | 3B | ; | |
| 00111100 | 60 | 3C | < | |
| 00111101 | 61 | 3D | = | |
| 00111110 | 62 | 3E | > | |
| 00111111 | 63 | 3F | ? | |
| 01000000 | 64 | 40 | @ | |
| 01000001 | 65 | 41 | A | |
| 01000010 | 66 | 42 | B | |
| 01000011 | 67 | 43 | C | |
| 01000100 | 68 | 44 | D | |
| 01000101 | 69 | 45 | E | |
| 01000110 | 70 | 46 | F | |
| 01000111 | 71 | 47 | G | |
| 01001000 | 72 | 48 | H | |
| 01001001 | 73 | 49 | I | |
| 01001010 | 74 | 4A | J | |
| 01001011 | 75 | 4B | K | |
| 01001100 | 76 | 4C | L | |
| 01001101 | 77 | 4D | M | |
| 01001110 | 78 | 4E | N | |
| 01001111 | 79 | 4F | O | |
| 01010000 | 80 | 50 | P | |
| 01010001 | 81 | 51 | Q | |
| 01010010 | 82 | 52 | R | |
| 01010011 | 83 | 53 | S | |
| 01010100 | 84 | 54 | T | |
| 01010101 | 85 | 55 | U | |
| 01010110 | 86 | 56 | V | |
| 01010111 | 87 | 57 | W | |
| 01011000 | 88 | 58 | X | |
| 01011001 | 89 | 59 | Y | |
| 01011010 | 90 | 5A | Z | |
| 01011011 | 91 | 5B | [ | |
| 01011100 | 92 | 5C | \ | |
| 01011101 | 93 | 5D | ] | |
| 01011110 | 94 | 5E | ^ | |
| 01011111 | 95 | 5F | _ | |
| 01100000 | 96 | 60 | ` | |
| 01100001 | 97 | 61 | a | |
| 01100010 | 98 | 62 | b | |
| 01100011 | 99 | 63 | c | |
| 01100100 | 100 | 64 | d | |
| 01100101 | 101 | 65 | e | |
| 01100110 | 102 | 66 | f | |
| 01100111 | 103 | 67 | g | |
| 01101000 | 104 | 68 | h | |
| 01101001 | 105 | 69 | i | |
| 01101010 | 106 | 6A | j | |
| 01101011 | 107 | 6B | k | |
| 01101100 | 108 | 6C | l | |
| 01101101 | 109 | 6D | m | |
| 01101110 | 110 | 6E | n | |
| 01101111 | 111 | 6F | o | |
| 01110000 | 112 | 70 | p | |
| 01110001 | 113 | 71 | q | |
| 01110010 | 114 | 72 | r | |
| 01110011 | 115 | 73 | s | |
| 01110100 | 116 | 74 | t | |
| 01110101 | 117 | 75 | u | |
| 01110110 | 118 | 76 | v | |
| 01110111 | 119 | 77 | w | |
| 01111000 | 120 | 78 | x | |
| 01111001 | 121 | 79 | y | |
| 01111010 | 122 | 7A | z | |
| 01111011 | 123 | 7B | { | |
| 01111100 | 124 | 7C | | | |
| 01111101 | 125 | 7D | } | |
| 01111110 | 126 | 7E | ~ | |
| 01111111 | 127 | 7F | DEL (delete) | 删除 |
第3部分:?扩展ASCII打印字符
| DEC | OCT | HEX | BIN | Symbol | HTML Number | HTML Name | Description |
|---|---|---|---|---|---|---|---|
| 128 | 200 | 80 | 10000000 | ? | € | € | Euro sign |
| 129 | 201 | 81 | 10000001 | ||||
| 130 | 202 | 82 | 10000010 | ? | ‚ | ‚ | Single low-9 quotation mark |
| 131 | 203 | 83 | 10000011 | ? | ƒ | ƒ | Latin small letter f with hook |
| 132 | 204 | 84 | 10000100 | ? | „ | „ | Double low-9 quotation mark |
| 133 | 205 | 85 | 10000101 | … | … | … | Horizontal ellipsis |
| 134 | 206 | 86 | 10000110 | ? | † | † | Dagger |
| 135 | 207 | 87 | 10000111 | ? | ‡ | ‡ | Double dagger |
| 136 | 210 | 88 | 10001000 | ? | ˆ | ˆ | Modifier letter circumflex accent |
| 137 | 211 | 89 | 10001001 | ‰ | ‰ | ‰ | Per mille sign |
| 138 | 212 | 8A | 10001010 | ? | Š | Š | Latin capital letter S with caron |
| 139 | 213 | 8B | 10001011 | ? | ‹ | ‹ | Single left-pointing angle quotation |
| 140 | 214 | 8C | 10001100 | ? | Π| Π| Latin capital ligature OE |
| 141 | 215 | 8D | 10001101 | ||||
| 142 | 216 | 8E | 10001110 | ? | Ž | Latin captial letter Z with caron | |
| 143 | 217 | 8F | 10001111 | ||||
| 144 | 220 | 90 | 10010000 | ||||
| 145 | 221 | 91 | 10010001 | ‘ | ‘ | ‘ | Left single quotation mark |
| 146 | 222 | 92 | 10010010 | ’ | ’ | ’ | Right single quotation mark |
| 147 | 223 | 93 | 10010011 | “ | “ | “ | Left double quotation mark |
| 148 | 224 | 94 | 10010100 | ” | ” | ” | Right double quotation mark |
| 149 | 225 | 95 | 10010101 | ? | • | • | Bullet |
| 150 | 226 | 96 | 10010110 | – | – | – | En dash |
| 151 | 227 | 97 | 10010111 | — | — | — | Em dash |
| 152 | 230 | 98 | 10011000 | ? | ˜ | ˜ | Small tilde |
| 153 | 231 | 99 | 10011001 | ? | ™ | ™ | Trade mark sign |
| 154 | 232 | 9A | 10011010 | ? | š | š | Latin small letter S with caron |
| 155 | 233 | 9B | 10011011 | ? | › | › | Single right-pointing angle quotation mark |
| 156 | 234 | 9C | 10011100 | ? | œ | œ | Latin small ligature oe |
| 157 | 235 | 9D | 10011101 | ||||
| 158 | 236 | 9E | 10011110 | ? | ž | Latin small letter z with caron | |
| 159 | 237 | 9F | 10011111 | ? | Ÿ | Ÿ | Latin capital letter Y with diaeresis |
| 160 | 240 | A0 | 10100000 |   | | Non-breaking space | |
| 161 | 241 | A1 | 10100001 | ? | ¡ | ¡ | Inverted exclamation mark |
| 162 | 242 | A2 | 10100010 | ? | ¢ | ¢ | Cent sign |
| 163 | 243 | A3 | 10100011 | ? | £ | £ | Pound sign |
| 164 | 244 | A4 | 10100100 | ¤ | ¤ | ¤ | Currency sign |
| 165 | 245 | A5 | 10100101 | ? | ¥ | ¥ | Yen sign |
| 166 | 246 | A6 | 10100110 | ? | ¦ | ¦ | Pipe, Broken vertical bar |
| 167 | 247 | A7 | 10100111 | § | § | § | Section sign |
| 168 | 250 | A8 | 10101000 | ¨ | ¨ | ¨ | Spacing diaeresis – umlaut |
| 169 | 251 | A9 | 10101001 | ? | © | © | Copyright sign |
| 170 | 252 | AA | 10101010 | ? | ª | ª | Feminine ordinal indicator |
| 171 | 253 | AB | 10101011 | ? | « | « | Left double angle quotes |
| 172 | 254 | AC | 10101100 | ? | ¬ | ¬ | Not sign |
| 173 | 255 | AD | 10101101 | ­ | ­ | Soft hyphen | |
| 174 | 256 | AE | 10101110 | ? | ® | ® | Registered trade mark sign |
| 175 | 257 | AF | 10101111 | ? | ¯ | ¯ | Spacing macron – overline |
| 176 | 260 | B0 | 10110000 | ° | ° | ° | Degree sign |
| 177 | 261 | B1 | 10110001 | ± | ± | ± | Plus-or-minus sign |
| 178 | 262 | B2 | 10110010 | ? | ² | ² | Superscript two – squared |
| 179 | 263 | B3 | 10110011 | ? | ³ | ³ | Superscript three – cubed |
| 180 | 264 | B4 | 10110100 | ? | ´ | ´ | Acute accent – spacing acute |
| 181 | 265 | B5 | 10110101 | ? | µ | µ | Micro sign |
| 182 | 266 | B6 | 10110110 | ? | ¶ | ¶ | Pilcrow sign – paragraph sign |
| 183 | 267 | B7 | 10110111 | · | · | · | Middle dot – Georgian comma |
| 184 | 270 | B8 | 10111000 | ? | ¸ | ¸ | Spacing cedilla |
| 185 | 271 | B9 | 10111001 | ? | ¹ | ¹ | Superscript one |
| 186 | 272 | BA | 10111010 | ? | º | º | Masculine ordinal indicator |
| 187 | 273 | BB | 10111011 | ? | » | » | Right double angle quotes |
| 188 | 274 | BC | 10111100 | ? | ¼ | ¼ | Fraction one quarter |
| 189 | 275 | BD | 10111101 | ? | ½ | ½ | Fraction one half |
| 190 | 276 | BE | 10111110 | ? | ¾ | ¾ | Fraction three quarters |
| 191 | 277 | BF | 10111111 | ? | ¿ | ¿ | Inverted question mark |
| 192 | 300 | C0 | 11000000 | ? | À | À | Latin capital letter A with grave |
| 193 | 301 | C1 | 11000001 | ? | Á | Á | Latin capital letter A with acute |
| 194 | 302 | C2 | 11000010 | ? | Â | Â | Latin capital letter A with circumflex |
| 195 | 303 | C3 | 11000011 | ? | Ã | Ã | Latin capital letter A with tilde |
| 196 | 304 | C4 | 11000100 | ? | Ä | Ä | Latin capital letter A with diaeresis |
| 197 | 305 | C5 | 11000101 | ? | Å | Å | Latin capital letter A with ring above |
| 198 | 306 | C6 | 11000110 | ? | Æ | Æ | Latin capital letter AE |
| 199 | 307 | C7 | 11000111 | ? | Ç | Ç | Latin capital letter C with cedilla |
| 200 | 310 | C8 | 11001000 | ? | È | È | Latin capital letter E with grave |
| 201 | 311 | C9 | 11001001 | ? | É | É | Latin capital letter E with acute |
| 202 | 312 | CA | 11001010 | ? | Ê | Ê | Latin capital letter E with circumflex |
| 203 | 313 | CB | 11001011 | ? | Ë | Ë | Latin capital letter E with diaeresis |
| 204 | 314 | CC | 11001100 | ? | Ì | Ì | Latin capital letter I with grave |
| 205 | 315 | CD | 11001101 | ? | Í | Í | Latin capital letter I with acute |
| 206 | 316 | CE | 11001110 | ? | Î | Î | Latin capital letter I with circumflex |
| 207 | 317 | CF | 11001111 | ? | Ï | Ï | Latin capital letter I with diaeresis |
| 208 | 320 | D0 | 11010000 | ? | Ð | Ð | Latin capital letter ETH |
| 209 | 321 | D1 | 11010001 | ? | Ñ | Ñ | Latin capital letter N with tilde |
| 210 | 322 | D2 | 11010010 | ? | Ò | Ò | Latin capital letter O with grave |
| 211 | 323 | D3 | 11010011 | ? | Ó | Ó | Latin capital letter O with acute |
| 212 | 324 | D4 | 11010100 | ? | Ô | Ô | Latin capital letter O with circumflex |
| 213 | 325 | D5 | 11010101 | ? | Õ | Õ | Latin capital letter O with tilde |
| 214 | 326 | D6 | 11010110 | ? | Ö | Ö | Latin capital letter O with diaeresis |
| 215 | 327 | D7 | 11010111 | × | × | × | Multiplication sign |
| 216 | 330 | D8 | 11011000 | ? | Ø | Ø | Latin capital letter O with slash |
| 217 | 331 | D9 | 11011001 | ? | Ù | Ù | Latin capital letter U with grave |
| 218 | 332 | DA | 11011010 | ? | Ú | Ú | Latin capital letter U with acute |
| 219 | 333 | DB | 11011011 | ? | Û | Û | Latin capital letter U with circumflex |
| 220 | 334 | DC | 11011100 | ? | Ü | Ü | Latin capital letter U with diaeresis |
| 221 | 335 | DD | 11011101 | ? | Ý | Ý | Latin capital letter Y with acute |
| 222 | 336 | DE | 11011110 | ? | Þ | Þ | Latin capital letter THORN |
| 223 | 337 | DF | 11011111 | ? | ß | ß | Latin small letter sharp s – ess-zed |
| 224 | 340 | E0 | 11100000 | à | à | à | Latin small letter a with grave |
| 225 | 341 | E1 | 11100001 | á | á | á | Latin small letter a with acute |
| 226 | 342 | E2 | 11100010 | ? | â | â | Latin small letter a with circumflex |
| 227 | 343 | E3 | 11100011 | ? | ã | ã | Latin small letter a with tilde |
| 228 | 344 | E4 | 11100100 | ? | ä | ä | Latin small letter a with diaeresis |
| 229 | 345 | E5 | 11100101 | ? | å | å | Latin small letter a with ring above |
| 230 | 346 | E6 | 11100110 | ? | æ | æ | Latin small letter ae |
| 231 | 347 | E7 | 11100111 | ? | ç | ç | Latin small letter c with cedilla |
| 232 | 350 | E8 | 11101000 | è | è | è | Latin small letter e with grave |
| 233 | 351 | E9 | 11101001 | é | é | é | Latin small letter e with acute |
| 234 | 352 | EA | 11101010 | ê | ê | ê | Latin small letter e with circumflex |
| 235 | 353 | EB | 11101011 | ? | ë | ë | Latin small letter e with diaeresis |
| 236 | 354 | EC | 11101100 | ì | ì | ì | Latin small letter i with grave |
| 237 | 355 | ED | 11101101 | í | í | í | Latin small letter i with acute |
| 238 | 356 | EE | 11101110 | ? | î | î | Latin small letter i with circumflex |
| 239 | 357 | EF | 11101111 | ? | ï | ï | Latin small letter i with diaeresis |
| 240 | 360 | F0 | 11110000 | ? | ð | ð | Latin small letter eth |
| 241 | 361 | F1 | 11110001 | ? | ñ | ñ | Latin small letter n with tilde |
| 242 | 362 | F2 | 11110010 | ò | ò | ò | Latin small letter o with grave |
| 243 | 363 | F3 | 11110011 | ó | ó | ó | Latin small letter o with acute |
| 244 | 364 | F4 | 11110100 | ? | ô | ô | Latin small letter o with circumflex |
| 245 | 365 | F5 | 11110101 | ? | õ | õ | Latin small letter o with tilde |
| 246 | 366 | F6 | 11110110 | ? | ö | ö | Latin small letter o with diaeresis |
| 247 | 367 | F7 | 11110111 | ÷ | ÷ | ÷ | Division sign |
| 248 | 370 | F8 | 11111000 | ? | ø | ø | Latin small letter o with slash |
| 249 | 371 | F9 | 11111001 | ù | ù | ù | Latin small letter u with grave |
| 250 | 372 | FA | 11111010 | ú | ú | ú | Latin small letter u with acute |
| 251 | 373 | FB | 11111011 | ? | û | û | Latin small letter u with circumflex |
| 252 | 374 | FC | 11111100 | ü | ü | ü | Latin small letter u with diaeresis |
| 253 | 375 | FD | 11111101 | ? | ý | ý | Latin small letter y with acute |
| 254 | 376 | FE | 11111110 | ? | þ | þ | Latin small letter thorn |
| 255 | 377 | FF | 11111111 | ? | ÿ | ÿ | Latin small letter y with diaeresis |