HEX HeroASCII to Hexadecimal Converter
Convert ASCII characters to hexadecimal format instantly with our free online tool. Enter any ASCII text and get immediate hex output—no signup needed. Perfect for developers, students, and anyone working with character encoding.
How to Convert ASCII to Hex
Input 7-Bit Characters
Enter ASCII text (A-Z, 0-9, symbols) or control codes
See Single-Byte Codes
Each character maps to one hex byte (00-7F range)
Export for Protocols
Copy hex for serial communication or firmware code
Configure Output Style
Choose 0x prefix format for C code or space-separated
ASCII to Hex Conversion Examples
| ASCII Input | Hex Output | Description |
|---|---|---|
| ESC[0m | 1B 5B 30 6D | ANSI escape sequence (terminal control) |
| CR+LF | 0D 0A | Windows line ending (control codes) |
| ACK | 06 | Acknowledge signal (serial communication) |
| RS-232 | 52 53 2D 32 33 32 | Protocol name (legacy systems) |
| ^C | 03 | Ctrl+C interrupt (control character) |
What is ASCII to Hex Conversion?
ASCII to hex conversion is the backbone of legacy system communication and embedded programming. Developed in 1963, ASCII established the first standardized character encoding system, defining exactly 128 characters using 7-bit values (0-127). Converting ASCII to hexadecimal creates compact two-digit codes—uppercase 'A' becomes 41, lowercase 'z' becomes 7A—making it ideal for serial communication protocols, terminal commands, and firmware development where byte-level precision matters.
This encoding method remains critical for embedded systems, retro computing, and industrial equipment that require strict 7-bit compatibility. Unlike modern Unicode encodings, ASCII guarantees single-byte representation with universal hardware support dating back decades. Engineers use ASCII hex values for protocol design, control character sequences (like Carriage Return = 0D), and debugging low-level communication. To decode hex back to ASCII characters, use our Hex to ASCII converter. Reference all 128 character codes in our comprehensive ASCII to Hex table.
ASCII Character Set: Quick Reference for Serial Communication
These hex ranges are critical for embedded systems and firmware development where precise 7-bit encoding matters.
Serial Protocol Characters
Embedded System Codes
Common Use Cases for ASCII to Hex Encoding
Serial & Terminal Communication
- • RS-232/RS-485 protocol design
- • UART configuration strings
- • Modem AT command encoding
- • VT100 terminal escape codes
Embedded Systems & Firmware
- • Bootloader message encoding
- • EEPROM configuration data
- • Microcontroller debug output
- • Arduino/PIC serial commands
Retro Computing & Legacy Systems
- • C64/Amiga hex listings
- • ROM image text extraction
- • DOS control character codes
- • BBS ANSI art encoding
Key Benefits of ASCII Hex Encoding
7-Bit Encoding Standard
Perfect for legacy system compatibility
Control Character Support
All 128 ASCII codes including non-printables
Embedded Systems Ready
Lightweight encoding for microcontrollers
Terminal Protocol Compatible
Works with serial communications
Backward Compatible
Universal support across all platforms
Understanding ASCII Encoding to Hexadecimal
ASCII encoding was designed in the 1960s for teletype machines and early computers, using 7 bits to represent 128 characters (hex 00-7F). The first 32 codes (00-1F) were reserved for device control—commands like Bell (07 to ring terminal bells), Backspace (08), and Escape (1B) that controlled hardware behavior. Code 7F (DEL) was originally used to mark deleted characters on paper tape by punching all holes.
The printable range (20-7E) follows a logical structure: digits 0-9 start at hex 30, uppercase A-Z begins at 41, and lowercase a-z starts at 61. This 32-value offset between uppercase and lowercase (hex 20) made case conversion trivial with a single bit flip. Special characters like @ (40), [ (5B), and ~ (7E) fill gaps in the layout, designed for programming languages like C and UNIX command syntax.
ASCII's 7-bit design left the 8th bit available for parity checking in early serial communication, ensuring data integrity over noisy telephone lines. Modern systems still use ASCII as the foundation—UTF-8's first 128 characters (00-7F) are identical to ASCII for backward compatibility. For firmware, embedded systems, and serial protocols, use our ASCII to Hex converter. Check the ASCII to Hex table for complete control code documentation.
ASCII Conversion FAQ
Why does ASCII use only 7 bits instead of 8?
ASCII was designed for teletype machines that reserved the 8th bit for parity checking, ensuring data integrity over noisy telephone lines. This 7-bit design (0-127 range) became the foundation for all modern character encodings.
How do I send control codes like STX and ETX in serial protocols?
Convert control character names to hex (STX=02, ETX=03, ACK=06) and send these bytes directly. Many embedded systems use STX/ETX for packet framing and ACK/NAK for handshakes.
What's the difference between CR, LF, and CRLF in ASCII?
CR (0D) moves cursor to line start, LF (0A) advances one line. CRLF (0D 0A) combines both for Windows line endings, while Unix uses just LF. Legacy Mac systems used CR alone.
Can ASCII encode terminal ANSI color codes?
Yes! ANSI escape sequences use pure ASCII. ESC[31m (red text) converts to 1B 5B 33 31 6D in hex. Terminal emulators interpret these control sequences to display colors and formatting.
Why is the DEL character positioned at hex 7F instead of 00-1F?
On paper tape systems, DEL (7F = all bits set) was created by punching holes over existing characters to "delete" them. This made 7F the natural choice for the delete operation.
How does ASCII differ from Extended ASCII (ISO-8859-1)?
Standard ASCII uses only 00-7F (128 chars). Extended ASCII adds 80-FF for accented characters (é, ñ, ü), but isn't standardized. For reliable international text, use UTF-8 instead.
Convert hexadecimal numbers to ASCII characters.
Convert text characters to hexadecimal numbers.
Convert a string of characters to hexadecimal numbers.
Convert UTF8 characters to hexadecimal numbers.
ASCII to hex conversion table.