BCD to Decimal Converter Online Free Tool
Convert packed BCD to decimal - binary or hex input, COMP-3 signed nibbles, batch mode. Free, client-side, instant, offline, secure.
Decode packed Binary-Coded Decimal into its decimal value. Accepts binary (00010010) or hex (12 / 0x12) input, handles IBM COBOL COMP-3 signed nibbles, processes one value per line.
How to Use BCD to Decimal Converter Online Free Tool
- Paste your BCD values into the input, one per line. Mix formats freely - each line is auto-detected independently (binary vs hex) unless you force a specific mode.
- Check the format mode. Auto-detect picks binary if every character is 0 or 1, otherwise hex. Force binary or hex if your input is ambiguous (e.g.
10could be binary "1 0" or hex "0x10"). - Toggle COMP-3 if needed. Mainframe / COBOL data uses a sign nibble at the very end:
CorFmeans positive,Dmeans negative. Without this toggle, a trailingC/D/Fwill error as "nibble exceeds 9". - Watch the stats line. You’ll see total lines · nibbles read · digits produced · valid vs invalid counts · signed lines detected. Useful for verifying a large batch decoded cleanly.
- Read per-line errors. If one line has a bad nibble (say
1010= 0xA = 10, which isn’t a valid decimal digit in unsigned BCD), that line showsERROR: nibble "1010" (0xA) exceeds 9 at position Nin the output. Other lines decode normally. - Copy or download. Copy writes the output to clipboard; Download saves
bcd-decimal-<timestamp>.txt. - Keyboard shortcut:
Ctrl+Enter/Cmd+Enterruns convert + copy in one step.
Frequently Asked Questions
What is BCD?
Binary-Coded Decimal represents each decimal digit (0-9) using 4 binary bits. Packed BCD stores two digits per byte. It is used in calculators, financial systems, and legacy mainframe software (COBOL COMP-3).
What is COMP-3 sign handling?
COBOL COMP-3 packs decimal digits and ends with a 4-bit sign nibble: C or F for positive, D for negative. This tool decodes all three sign conventions correctly.
Can I input BCD as binary or hex?
Yes. Paste 8-bit binary strings like 00010010 or hex bytes like 12. The tool detects the format automatically.
What is batch mode?
Batch mode lets you convert many BCD values at once, one per line. Each line is decoded independently and the results are aligned for easy review or export.
Is my data secure?
Yes. Decoding happens entirely in your browser. Nothing is uploaded, logged, or stored.
Do you save my input?
No. The tool is 100% client-side.
Is this tool free?
Yes, no sign-up and no usage limits.
What if my BCD has invalid nibbles?
A valid BCD nibble is 0-9. If a nibble is A-F (except as a sign marker in COMP-3 mode), the tool flags it and shows exactly which byte contains the problem.
Can BCD represent numbers larger than 9?
Yes. Multiple BCD bytes are chained to represent large decimal numbers, with each byte holding two digits. The tool uses JavaScript BigInt for arbitrary precision.
Is BCD still used today?
It persists in financial systems, legacy mainframes running COBOL, some hardware displays (7-segment drivers), and barcode standards where exact decimal representation matters.