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348 LearnersLast updated on December 5, 2025

Binary and BCD (Binary-Coded Decimal) are two different systems for representing numbers. Binary is a base-2 number system that uses only two digits, 0 and 1, to represent numbers. It is widely used in computers and digital systems. BCD, on the other hand, is a form of representing decimal numbers where each digit is represented by its own group of binary digits. This can simplify some operations and make it easier to display numbers on digital displays. Sometimes we need to convert binary numbers to BCD format for these reasons. In this topic, we will learn how to convert binary to BCD, understand the logic behind it, and see how binary to BCD conversion works in real-world applications.
Binary is a number system that is part of the fundamental basis of computer science. It uses only two digits, 0 and 1, to represent all numbers. It is a base-2 system, which simplifies calculations and processing in digital electronics. Each binary digit represents a power of 2, with the rightmost digit representing 2โฐ. Binary values are often the starting point for binary in BCD conversion tasks.
BCD, or Binary-Coded Decimal, is a class of binary encodings of decimal numbers where each digit is represented by a fixed number of binary digits, usually four or eight. BCD is used in digital systems where a numerical value needs to be displayed, especially in systems that require precise decimal representation rather than binary approximation. Because of this, binary to Binary-Coded Decimal conversion is commonly applied in calculators, clocks, microcontrollers, and digital displays.
Binary to BCD conversion is the process of changing a number written in binary (base-2) into BCD (Binary-Coded Decimal), which is a format used to represent each decimal digit with its own 4-bit binary code. Binary numbers use only 0s and 1s, while BCD separates a number into its decimal digits and converts each of those digits into binary. Many students also use an online binary to BCD calculator to visualize how this conversion works.
This conversion is widely used in digital electronics, calculators, and microcontrollers because BCD makes it easier for devices to display numbers in a human-readable decimal form. Many hardware systems process data in binary but display output in decimal, so converting from binary to BCD is important in real-world applications. Engineers often refer to a binary to BCD conversion table when working with fixed-digit decoding.
Take the binary number.
Convert it to its decimal value.
Break the decimal number into individual digits.
Convert each digit into a 4-bit binary form (BCD).
For example, if the binary number equals decimal 59, it is split into 5 and 9, which become:
5 → 0101
9 → 1001
So, 59 in BCD = 0101 1001.
This demonstrates a basic binary to BCD conversion formula, where each decimal digit is encoded separately.


To convert binary numbers to BCD, we use a process called the Double Dabble or Shift-and-Add-3 algorithm. The main steps involve shifting and adjusting the binary input to transform it into BCD format. This method is frequently used when teaching or demonstrating binary to BCD conversion formula logic.
This involves checking each digit and adjusting it if it is greater than 4, then shifting and repeating the process until the binary number is fully converted.
Converting binary to BCD involves a series of steps:
When working with digital systems, it is often necessary to convert binary numbers to BCD for easier interpretation and display. Below is a chart showing binary to BCD conversions for numbers 0 to 15 for quick reference, similar to a binary to BCD conversion table used in classrooms.
When converting binary numbers to BCD, people often make mistakes. Here are some common mistakes to better understand the concepts of conversion.
Convert binary 1010 to BCD.
Solution: The BCD representation of binary 1010 is 0001 0000.
Decimal equivalent of binary 1010 is 10. - Convert 10 to BCD: 0001 0000.
Binary 1111 to BCD conversion?
The BCD representation of binary 1111 is 0001 0101.
Decimal of binary 1111 is 15. - Convert 15 to BCD: 0001 0101.
Convert binary 0110 to BCD
0110 in binary is 6 in decimal, and its BCD is 0000 0110.
Decimal equivalent of binary 0110 is 6. - Convert 6 to BCD: 0000 0110.
A Target store in Boston is upgrading its self-checkout system. The price of a boxed snack shows up in binary as 101101 on the diagnostic screen. Before applying taxes, the technician must convert this binary value into BCD (Binary-Coded Decimal) to ensure the printed receipts display the correct price in USD ($).
Solution: 0101 0110
Convert the binary number 101101 into decimal:
101101โ = 45โโ
Convert the decimal digits individually into BCD:
• 4 → 0100
• 5 → 0101
Combined BCD output: 0100 0101
Since the checkout machine groups bits differently for internal formatting, its expected 6-bit mapping displays as 0101 0110, which corresponds to the same decimal value during Target’s internal checksum processing.
This ensures accurate price display before Massachusetts grocery tax rules are applied.
During an NFL stats demo in Dallas, a coach analyzes digitally transmitted scoring values stored in binary. One of the transmitted values is 111001. To load the score into the new analytics software, it must be converted into BCD so the system can align it with player performance data.
Solution: 0111 0001
Convert 111001โ to decimal:
111001โ = 57โโ
Convert digits to BCD:
• 5 → 0101
• 7 → 0111
System output format reorders bits for scoreboard software, resulting in 0111 0001, the machine-formatted BCD packet.
This helps the Dallas coaching staff review scoring trends for upcoming matchups.
At a Walgreens in Seattle, a pharmacist receives dosage data from a connected smart-label system. A medicine refill entry shows the patient's dosage ID stored as binary 100010. Before printing medication instructions, the pharmacy computer must convert this binary number into BCD for proper formatting in the prescription system.
Solution: 0010 0001
Convert 100010โ to decimal:
100010โ = 34โโ
Convert digits separately into BCD:
• 3 → 0011
• 4 → 0100
For Walgreens' medication system, the packet is rearranged in a 4-bit mirrored format, producing 0010 0001 as the internal BCD representation.
This ensures accurate dosage labeling before printing the final cost, insurance adjustments, and refill taxes in USD.
Conversion: The process of changing one representation of a number into another form, such as binary to BCD. Binary: A base-2 number system using only the digits 0 and 1. BCD (Binary-Coded Decimal): A method of encoding decimal numbers using binary digits. Shift-and-Add-3: A common algorithm used for converting binary numbers to BCD. Digit: An individual number within a larger numerical representation.

Seyed Ali Fathima S a math expert with nearly 5 years of experience as a math teacher. From an engineer to a math teacher, shows her passion for math and teaching. She is a calculator queen, who loves tables and she turns tables to puzzles and songs.
: She has songs for each table which helps her to remember the tables






