BCD to Octal Converter Free Online Tool
Convert BCD to octal - 0o / 0 / no prefix, COMP-3 sign, BigInt precision, batch mode. Free, client-side, instant, offline, secure.
Decode Binary-Coded Decimal to base-8 (octal). Pipeline is BCD → decimal value → octal, with choice of 0o, 0, or no prefix. BigInt arithmetic for arbitrary lengths, COMP-3 sign nibble support, batch mode.
How to Use BCD to Octal Converter Free Online Tool
- Paste BCD values, one per line. Binary (
0001 0010) and hex (12or0x12) are both accepted; each line is auto-detected or you can force a format. - Pick a prefix style.
0ois the Python 3 / modern JS convention.0is traditional C / bash / old Unix.Nonegives bare octal digits for pasting into custom parsers. - Turn on COMP-3 for mainframe / COBOL data. The last nibble (
C/F= positive,D= negative) is parsed as a sign indicator, and a negative value gets a-prefix in the output. - Watch the stats line: total lines · nibble count · decimal + octal digit counts · ✓valid or ⚠invalid · signed count. Useful for verifying a batch decoded correctly.
- Check errors inline. Bad lines show
ERROR: nibble "1010" (0xA) exceeds 9 at position Nright where the hex output would go. Other lines still convert successfully. - Copy or download. Copy writes to clipboard, Download saves
bcd-octal-<timestamp>.txt. Keyboard shortcut:Ctrl+Enter/Cmd+Enterruns convert + copy. - Reset options returns all controls to defaults and re-runs the current input so you can see what changed.
Frequently Asked Questions
What is octal and when is it used?
Octal is base 8, using digits 0-7. It is common in Unix file permissions (chmod 755), some hardware addresses, and older computing contexts. Each octal digit maps to 3 binary bits.
What prefix options does the tool offer?
You can output with 0o prefix (modern Python, ECMAScript), 0 prefix (traditional C, shell), or no prefix for raw digits. Pick the one that matches your target system.
What is the COMP-3 sign option?
COBOL COMP-3 BCD uses the last nibble as a sign marker (C or F positive, D negative). Enabling this option makes the tool read that nibble and output a signed octal result.
Why do I need BigInt precision?
Packed BCD can represent very large numbers without rounding. BigInt ensures that a 15-digit BCD decimal value produces an exact octal equivalent, not a truncated approximation.
Is the tool secure?
Yes. All conversions run in your browser. Your BCD inputs and octal outputs stay on your device.
Does it save my data?
No. The tool is fully client-side with no logging or storage.
Is this free?
Yes, completely free with no sign-up.
What about invalid BCD?
The tool validates every nibble and reports the exact position of invalid digits so you can correct the input quickly.
Can I batch-convert many values?
Yes. Paste one BCD value per line and the tool outputs each octal conversion on its own line, aligned for readability.
Where would I use octal output?
Classic Unix permissions (chmod, umask), some embedded microcontroller documentation, aviation systems, and legacy file formats still use octal notation.