What input format does this tool expect?

A binary string made up only of 0s and 1s, whose length is a multiple of 4 bits, split into one 4-bit nibble per decimal digit. For example, "00110001" is two nibbles, 0011 and 0001, representing the decimal digits 3 and 1 (decimal 31).

What happens if a nibble isn't valid BCD?

Any nibble with the bit pattern 1010 through 1111 (decimal 10-15) isn't a valid BCD digit, since BCD only ever encodes 0-9. The tool rejects the input and names exactly which nibble (by position) is invalid, so you can find and fix the problem quickly.

How is the final hex value computed?

Each nibble is decoded to its decimal digit (0-9), the digits are concatenated in order into a full decimal string, that string is parsed as an exact integer using BigInt, and the result is formatted as uppercase hexadecimal.

Does the input need to be a multiple of 4 bits?

Yes. Since BCD assigns exactly one 4-bit nibble per decimal digit, any input whose length isn't a multiple of 4 can't be split cleanly into nibbles and is rejected with an error stating the actual bit count received.

How does this differ from the Hex to BCD Converter?

Hex to BCD Converter goes the other direction: it takes a hexadecimal value and produces its BCD binary encoding. This tool takes BCD binary input and produces the equivalent hexadecimal value, the exact inverse operation.

BCD to Hex Converter - Binary-Coded Decimal to Hexadecimal Online

Overview

Introduction

BCD stores each decimal digit as its own 4-bit nibble, which is convenient for digital displays and clock hardware but needs decoding before it can be used as an ordinary hexadecimal or decimal value elsewhere.

This tool takes a BCD binary string and decodes it back into the decimal value it represents, then displays that value as hexadecimal.

What Is BCD to Hex Converter?

A decoder that reads a Binary-Coded Decimal binary string, splits it into 4-bit nibbles, validates and decodes each nibble as a decimal digit, and outputs the reassembled value as hexadecimal.

It's the direct inverse of Hex to BCD Converter: encode a hex value to BCD with that tool, then decode it back with this one to confirm the round trip.

How BCD to Hex Converter Works

The input is stripped of whitespace and validated as a binary string whose length is a multiple of 4, then split into consecutive 4-bit nibbles.

Each nibble is parsed as a binary number and checked to be within the valid BCD range of 0-9; if any nibble falls in the invalid 10-15 range, decoding stops immediately with an error naming that nibble's position. Otherwise, the decoded digits are joined into a decimal string, parsed as an exact BigInt, and formatted as uppercase hexadecimal.

When To Use BCD to Hex Converter

Use it whenever you have a BCD-encoded reading from a real-time clock chip, seven-segment display driver, or legacy decimal system and need it converted to ordinary hexadecimal for further processing.

It's also the natural companion to Hex to BCD Converter for verifying an encoding by round-tripping a value through both tools.

Often used alongside Hex to BCD Converter and Decimal to Hex Converter.

Features

Advantages

Validates every nibble is genuinely valid BCD (0-9) before decoding, rather than silently accepting invalid 10-15 patterns.
Pinpoints exactly which nibble and bit positions are invalid when validation fails, making mistakes easy to locate.
Uses BigInt internally, so decoding stays exact even for BCD strings representing large values.

Limitations

Only accepts strings of 0s and 1s whose length is a multiple of 4; any other length or character set is rejected rather than guessed at.
There is no built-in support for a BCD sign nibble or sign convention, since none is standardized.

Examples

Decoding a two-nibble BCD value

Input

00110001

Output

1F

Nibbles 0011 and 0001 decode to digits 3 and 1, giving decimal 31, which is hex 1F.

Decoding a three-nibble BCD value

Input

001001010101

Output

FF

Nibbles 0010, 0101, 0101 decode to digits 2, 5, 5, giving decimal 255, which is hex FF.

Best Practices & Notes

Best Practices

If decoding fails, check the nibble position named in the error first; it's almost always a transposed or corrupted 4-bit group rather than a problem with the whole string.
Use Hex to BCD Converter on the result to round-trip and confirm you recover your original BCD string.

Developer Notes

Validation splits the cleaned binary string into 4-bit chunks and calls `parseInt(nibble, 2)` on each, rejecting any value greater than 9 with an error that includes the 1-based nibble index and its bit range, before joining the decoded digits and passing them to `BigInt(...)` for exact hex formatting.

BCD to Hex Converter Use Cases

Decoding BCD readings from real-time clock chips or seven-segment display drivers back into hex
Verifying a Hex to BCD Converter encoding by round-tripping it back to hex
Validating that a BCD data stream contains only legitimate decimal-digit nibbles

Common Mistakes

Feeding in plain (non-BCD) binary and expecting a meaningful result; if any 4-bit group happens to fall in the 10-15 range, decoding will correctly fail rather than guess.
Providing a bit count that isn't a multiple of 4, which can't be split into whole nibbles and is rejected outright.
Assuming leading zero nibbles are errors; a leading 0000 nibble is perfectly valid BCD for a leading zero digit.

Tips

Pair this with Hex to BCD Converter to round-trip and sanity-check any manual BCD work.
When debugging a rejected nibble, count in groups of 4 from the start of your string; the error's bit range makes this easy to line up.

BCD to Hex Converter