BCD Converter
Decimal ⇄ 8421 BCD — 4 bits per digit.
What it does: Convert between decimal and BCD.
When to use it: When driving 7-segment displays or building electronic clock / instrument displays.
MEANS Every 4 bits form one group, corresponding to one decimal digit.
No history yet. Each calculation is automatically saved to this device.
How to use the BCD converter
Choose a direction and enter a value.
- 01
Choose a direction
Decimal→BCD or BCD→decimal.
- 02
Enter
For decimal, enter an integer; for BCD, enter a 0/1 bit string (in groups of 4).
- 03
Read the result
BCD is shown in groups of 4 bits, each group corresponding to one decimal digit.
Common questions, answered in 3 minutes
What's the difference between BCD and binary?
BCD encodes each decimal digit separately in 4 bits (e.g. 25=0010 0101), whereas binary converts the whole number (25=11001). BCD wastes space but makes decimal display/conversion simple.
Where is BCD used?
7-segment display drivers, electronic clocks, and instrument displays — driven directly by decimal digit, with no binary division needed.
Why are some 4-bit groups invalid?
Each BCD group can only be 0000–1001 (0–9); 1010–1111 are not valid BCD.
Standards and sources referenced by this tool
| Item | Value / Formula | Source |
|---|---|---|
| 8421 BCD | Each decimal digit → 4 bits | BCD encoding |
8421 BCD rules, no external API.