BCD Converter
Free online BCD converter. Convert decimal to Binary Coded Decimal and back. Shows packed BCD, unpacked BCD, and binary comparison. 8421 (natural) BCD for digital displays, clocks, and embedded systems. No signup required.
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What is BCD Converter?
A BCD Converter translates numbers between plain decimal and Binary Coded Decimal (BCD). In 8421 BCD - the most common form - each decimal digit (0-9) is written as a separate 4-bit nibble. This makes each digit directly readable, which is why BCD powers digital displays, clocks, and calculators even though it uses more bits than pure binary.
Key Benefits
- Instant two-way conversion between decimal and 8421 BCD
- Shows packed BCD, unpacked BCD, and binary together
- Validates every nibble - flags 1010 to 1111 as invalid
- Accepts both packed bits and space-separated nibble input
- 100% client-side - nothing is uploaded
Common Use Cases
- •Engineering students learning BCD vs. pure binary
- •Embedded developers driving 7-segment displays and RTC chips
- •Verifying BCD counters and digital-clock circuits
- •Anyone converting data for financial or decimal-exact systems
How to Use the BCD Converter
- Pick an input format: Choose Decimal or BCD as the format of the value you want to convert.
- Enter your value: Type a decimal number, or BCD bits (packed or space-separated nibbles). The tool converts automatically and validates the input.
- Read the outputs: The results show Decimal, Packed BCD, Unpacked BCD (nibble-separated), and plain Binary side by side so you can compare.
- Copy a result: Click Copy next to any output to copy it to your clipboard for use in schematics or code.
Key Features
- Two-way conversion: decimal to BCD and BCD to decimal
- Shows packed (continuous) and unpacked (nibble-separated) 8421 BCD forms
- Includes a pure-binary comparison so BCD vs. binary is clear
- Validates every nibble and rejects 1010 to 1111 as invalid BCD
- Accepts both packed bits and space-separated nibble input
- 100% client-side — your data never leaves the browser