ASCII to Decimal Converter: Text to Decimal Numbers
Translate ASCII text to decimal numbers instantly. See the numeric representation of every character, from basic Latin letters to control codes. Essential for computer science education and low-level programming.
How it works
This tool converts ASCII characters to their decimal code values. Each character in the ASCII table has a unique number from 0 to 127. The converter looks up each character and outputs its decimal equivalent.
For example, 'A' is 65, 'a' is 97, '0' is 48, and space is 32. The tool processes each character independently and shows the decimal values separated by spaces for readability.
Example conversions:
ABCbecomes65 66 67Hellobecomes72 101 108 108 111Type text to see decimal values instantly. The reverse conversion (decimal to ASCII) also works—paste space-separated numbers to get the text back.
When you'd actually use this
Learning ASCII encoding in computer science
A student studies how computers represent text internally. They convert their name to decimal ASCII values to understand that "72 101 108 108 111" is how the computer stores "Hello".
Debugging character encoding issues
A developer sees unexpected characters in output. They convert to decimal to discover a non-breaking space (160) instead of regular space (32), explaining the layout bug.
Writing character validation code
A programmer needs to validate input contains only digits. They check that character codes fall between 48 and 57 (ASCII for '0' through '9') to verify numeric input.
Creating CTF cryptography challenges
A cybersecurity competition organizer encodes flags as ASCII decimal values. Participants must recognize the pattern and convert back to text to find the hidden flag.
Processing legacy data formats
An engineer works with old systems that store text as decimal ASCII values. They convert between human-readable text and the decimal format for data migration.
Testing input sanitization functions
A QA engineer tests whether their sanitizer blocks control characters. They generate test cases with specific ASCII codes (like 0-31) to verify proper handling.
What to know before using it
ASCII only covers codes 0-127.Standard ASCII has 128 characters. Extended ASCII (128-255) varies by code page. Unicode characters above 255 need different handling than simple decimal conversion.
Control characters (0-31) aren't printable.Codes 0-31 are control characters like null, tab, newline. They don't display as visible characters but affect text formatting.
Case matters in ASCII.Uppercase 'A' is 65, lowercase 'a' is 97. The 32-point difference is consistent—flip bit 5 to toggle case in ASCII.
Space is ASCII 32, not zero.The space character has code 32. Code 0 is the null character, which marks string endings in C and can't be stored in regular strings.
Pro tip: Memorize key ASCII values: 32=space, 48-57=digits, 65-90=uppercase, 97-122=lowercase. These ranges help you quickly identify character types when debugging.
Common questions
What is ASCII code for 'A'?
'A' is ASCII code 65. Uppercase letters run from 65 ('A') to 90 ('Z'). Lowercase 'a' is 97, running to 122 for 'z'.
How do I convert decimal back to text?
Paste space-separated decimal numbers like "72 101 108 108 111" and the tool converts each to its ASCII character. 72 becomes 'H', 101 becomes 'e', spelling "Hello".
What's the ASCII code for newline?
Line feed (newline) is ASCII 10. Carriage return is 13. Windows uses both (13, 10) for line endings. Unix uses just 10. Old Mac used just 13.
Can I convert emoji to decimal?
Emoji are Unicode, not ASCII. They have code points above 127 and need multiple bytes in UTF-8. This tool handles ASCII only. Use a Unicode converter for emoji.
Why are there 128 ASCII characters?
ASCII uses 7 bits, giving 2^7 = 128 possible values (0-127). The 8th bit was sometimes used for parity checking or extended character sets.
What character is ASCII 0?
ASCII 0 is the null character, written as '\0'. It marks the end of strings in C and C++. You can't display it—it's a control character with no visual representation.
Is ASCII still used today?
Yes, ASCII is the foundation of Unicode. The first 128 Unicode code points match ASCII exactly. Most English text is still pure ASCII even in UTF-8 encoding.