BCD to Hex Converter Online Free Tool
Convert packed BCD to hexadecimal - decimal-value or nibble mode, BigInt precision, COMP-3 sign. Free, client-side, instant, offline, secure.
Convert Binary-Coded Decimal to hexadecimal. Pick between decimal-to-hex (BCD value → hex number) or nibble pass-through (each BCD nibble → hex digit). BigInt-based, handles arbitrary-length inputs, supports IBM COMP-3 sign nibbles.
How to Use BCD to Hex Converter Online Free Tool
- Paste BCD values, one per line. Each line is auto-detected as binary (all 0/1) or hex (digits + A-F) unless you force a specific format.
- Pick the conversion mode. Decimal-to-hex interprets BCD as a decimal number and converts to hex (
0001 0010= decimal 12 =0xC). Nibble pass-through copies each BCD nibble as a hex digit (0001 0010→0x12). Most users want the first. - Toggle uppercase if your downstream tool expects
A-F. Most modern APIs prefer lowercase. - Toggle 0x prefix based on where you paste the output. Source code in C / Rust / Go likes
0x; some hex editors or comparison tools want bare hex. - Enable COMP-3 signed if you’re decoding mainframe / COBOL data. The last nibble (
C/F= +,D= -) is treated as a sign indicator rather than a digit. - Watch the stats line. It shows total lines · nibbles · decimal digits · ✓valid or ⚠invalid · signed count · which conversion mode was used.
- Copy or download. Copy writes the output; Download saves
bcd-hex-<timestamp>.txt. Keyboard shortcut:Ctrl+Enter/Cmd+Enterruns convert + copy.
Frequently Asked Questions
What is BCD to hex conversion for?
It converts a BCD-encoded decimal value into its hexadecimal representation. This is useful when migrating data from COBOL systems to modern APIs or when inspecting memory dumps from legacy hardware.
What is the difference between value mode and nibble mode?
Value mode first decodes BCD to its decimal value, then converts that value to hex. Nibble mode reinterprets the same bytes directly as hex without converting the value (useful for raw memory views).
Does it handle COMP-3 sign nibbles?
Yes. In COMP-3 mode the tool reads the trailing sign nibble (C, D, or F) and produces a properly signed hex result.
Why do I need BigInt precision?
BCD can represent very large decimal numbers (dozens of digits) without precision loss. JavaScript BigInt preserves every digit through the conversion instead of rounding like floating-point would.
Is my data secure?
Yes. All processing runs in your browser. BCD inputs and hex outputs stay on your device.
Do you log anything?
No. The tool is fully client-side with no analytics on your actual data.
Is it free?
Yes, no sign-up and no limits.
Can I choose lowercase or uppercase hex?
Yes. A toggle switches between ff output and FF output for both value and nibble modes.
What if my input is not valid BCD?
The tool checks every nibble and reports invalid ones with their byte position, so you can spot corruption quickly.
Can I convert multiple BCD values at once?
Yes. Batch mode accepts one value per line and produces aligned hex output for easy comparison or export.