Hex to ASCII Converter
Decode hexadecimal values to ASCII text instantly with our free online tool. Enter hex bytes and get immediate ASCII output—no signup needed. Perfect for developers, reverse engineering, and data analysis.
How to Decode Hex to ASCII
Input Hex Dump
Paste bytes from firmware, memory dumps, or hex editors
Filter ASCII Range
Only bytes 00-7F decode; values above show as errors
Extract Readable Strings
Copy visible text patterns found in binary data
Identify Control Codes
Spot ESC, CR, LF, and NULL characters in output
Hex to ASCII Conversion Examples
Hexadecimal Input | ASCII Output | Description |
---|---|---|
1B 5B 33 31 6D | ESC[31m | ANSI color code (red text) |
00 01 02 03 | [NUL][SOH][STX][ETX] | Binary header control codes |
46 49 52 4D 57 41 52 45 | FIRMWARE | Firmware identifier in hex dump |
0D 0A | CRLF | DOS/Windows line ending sequence |
7E 7E 7E | ~~~ | Delimiter sequence (embedded systems) |
04 | EOT | End of Transmission control code |
What is Hex to ASCII Conversion?
Hex to ASCII decoding is the reverse engineering tool for analyzing binary files, memory dumps, and firmware images. When examining hex dumps from executables, ROM chips, or hardware devices, ASCII-range values (00-7F) often reveal embedded text strings—copyright notices, error messages, debugging output, and configuration data. Security researchers use this technique to extract readable strings from compiled binaries, while embedded systems engineers decode ANSI escape sequences and control codes that appear as cryptic hex values like 1B 5B 33 31 6D (which renders as ESC[31m for red terminal text).
The 7-bit ASCII limitation (maximum value 7F) makes decoding straightforward: any hex byte above 7F falls outside standard ASCII and may indicate extended characters, binary data, or encoding errors. Firmware developers regularly search hex dumps for ASCII patterns to locate string tables, command structures, and protocol markers. Control characters (00-1F, 7F) reveal formatting codes—0D 0A indicates Windows line endings, 00 marks null terminators in C strings, and values like 06 (ACK) appear in serial communication handshakes. To encode ASCII text back into hex format, use our ASCII to Hex converter.
ASCII Decoding Ranges: Firmware String Extraction
When analyzing hex dumps, these ranges help identify readable ASCII strings embedded in binary data versus code bytes.
Firmware String Indicators
Binary Dump Patterns
Common Use Cases for Hex to ASCII Decoding
Reverse Engineering
- • Analyze hex dumps from binary files
- • Read memory dump contents
- • Inspect firmware data structures
- • Extract strings from executables
Network & Security
- • Decode network packet payloads
- • Analyze protocol communications
- • Inspect security logs and traces
- • Forensics and incident response
Embedded & IoT Debugging
- • Arduino serial monitor output
- • ESP32/ESP8266 debug logs
- • JTAG debugger ASCII strings
- • Bootloader error messages
Hex to ASCII Decoder Features
Hex Dump Decoder
Read binary file hex dumps instantly
7-Bit Validation
Automatically validates ASCII range (00-7F)
Control Code Viewer
See non-printable characters
Retro Computing Tool
Debug vintage systems and protocols
Firmware Analysis
Inspect embedded system strings
Memory Dump Reader
Extract ASCII from memory captures
ANSI Code Support
Decode terminal escape sequences
Understanding ASCII Decoding from Hexadecimal
When reverse engineering firmware or analyzing binary protocols, hex dumps reveal ASCII strings embedded in compiled code—function names like 69 6E 69 74
(init), error messages, and version strings help identify functionality. Memory dumps from embedded devices often mix code bytes (outside ASCII range) with readable strings. Scanning for consecutive bytes in the 20-7E range extracts human-readable fragments from binary data.
Control character detection matters in protocol analysis: 1B 5B 33 31 6D
decodes to ESC[31m (ANSI red color code), 0D 0A
marks Windows line endings in network protocols, and 00
(NULL) terminates C strings. Serial communication logs show these control codes that affect terminal behavior but don't display as visible characters. The ASCII to Hex table documents all 128 codes.
Values above 7F indicate either high-bit-set ASCII variants (like extended ASCII where 80-FF represent accented characters) or the start of UTF-8 multi-byte sequences. Without context, C3 A9
could be two extended ASCII characters or UTF-8 é. Firmware often uses pure 7-bit ASCII to avoid encoding issues—any 80+ values suggest data corruption or different encoding. For UTF-8 decoding, use our Hex to UTF-8 converter. For encoding ASCII back, try ASCII to Hex.
Decoding Hex: Your Questions
How do I find ASCII strings in binary firmware files?
Use xxd or a hex editor to export hex, then decode here. Scan for consecutive bytes in the 20-7E range—these are printable ASCII. Error messages, version strings, and function names often appear this way.
Why do some bytes show as � or blank spaces?
Bytes 00-1F and 7F are non-printable control codes (NULL, CR, LF, ESC). Bytes 80-FF are outside ASCII range. Only 20-7E display as visible characters like letters, numbers, and symbols.
What does FF mean in ROM dumps or EEPROM chips?
FF (255) indicates unprogrammed or erased flash/EEPROM memory. Consecutive FF bytes suggest empty space or padding, not actual ASCII data. Look for patterns like 20-7E for real content.
How do debug logs encode NULL-terminated strings?
C strings end with 00 (NULL). For example, "OK" appears as 4F 4B 00 in memory dumps. The 00 byte marks string termination but won't display as a visible character.
Can I decode serial monitor output captured in hex?
Absolutely! Arduino, ESP32, and other microcontroller serial outputs can be captured as hex. Paste the hex bytes here to see the actual debug messages, including ANSI color codes if present.
What's the pattern for detecting ASCII in mixed binary data?
Look for runs of 5+ consecutive bytes in 20-7E range, often ending with 00. These clusters indicate embedded strings. Isolated bytes outside this range are likely binary data or UTF-8 sequences.
Convert ASCII characters to hexadecimal numbers.
Convert hexadecimal numbers to text characters.
Convert hexadecimal numbers to a string of characters.
Convert hexadecimal numbers to UTF8 characters.
ASCII to hex conversion table.