Convert Between Binary, Decimal, and Hexadecimal 🌎
Instantly convert between binary, decimal, and hexadecimal. Enter any number, pick your source and target base, get the result immediately. Includes a full reference table and step-by-step explanation.
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Your result
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Base conversion is a core skill in computer science, digital electronics, and programming. Binary (base 2) is the language processors use internally; hexadecimal (base 16) is how programmers read binary values compactly — each hex digit equals exactly 4 bits. This calculator converts between decimal, binary, and hexadecimal instantly using successive division (dec → other) or positional sum (other → dec).
When to use this calculator
Computer science homework: convert 1010 1100 binary to hexadecimal and decimal.
Subnet masks: convert 255.255.255.0 to binary (11111111.11111111.11111111.00000000 = /24).
Debugging in C or Python: the debugger shows 0x1F3A — what is the decimal value? (7994).
CSS colors: #FF00AA in decimal RGB → R=255, G=0, B=170.
Microcontroller registers: read bit flags from hex values directly.
Conversion Reference: Decimal, Binary (8-bit), and Hexadecimal
Decimal
Binary (8-bit)
Hexadecimal
0
0000 0000
00
1
0000 0001
01
9
0000 1001
09
10
0000 1010
0A
15
0000 1111
0F
16
0001 0000
10
42
0010 1010
2A
127
0111 1111
7F
128
1000 0000
80
255
1111 1111
FF
256
0001 0000 0000
100
1023
0011 1111 1111
3FF
65535
1111 1111 1111 1111
FFFF
Fuente: Wolfram MathWorld — Base (Number); valores verificados mediante división sucesiva y suma posicional según metodología estándar de conversión de bases.
How it works
How Base Conversion Works
Decimal → Binary or Hex (successive division)
1. Divide the number by the target base (2 for binary, 16 for hex). 2. Record the remainder (0–1 for binary; 0–F for hex). 3. Repeat with the quotient until it reaches 0. 4. Read the remainders from bottom to top.
Example: 42 decimal → binary
42 ÷ 2 = 21 r 0
21 ÷ 2 = 10 r 1
10 ÷ 2 = 5 r 0
5 ÷ 2 = 2 r 1
2 ÷ 2 = 1 r 0
1 ÷ 2 = 0 r 1
Result: 101010
Binary or Hex → Decimal (positional sum)
Each digit × base^position (position starts at 0 from the right).
Example: 101010 binary → decimal
1×2⁵ + 0×2⁴ + 1×2³ + 0×2² + 1×2¹ + 0×2⁰
32 + 0 + 8 + 0 + 2 + 0 = 42
Binary ↔ Hex (shortcut)
Group binary digits into sets of 4 from the right; each group = 1 hex digit.
1010 1100 → 1010 (A) 1100 (C) → AC
Conversion Reference Table
Decimal
Binary (8 bits)
Hex
0
0000 0000
00
1
0000 0001
01
9
0000 1001
09
10
0000 1010
0A
15
0000 1111
0F
16
0001 0000
10
42
0010 1010
2A
127
0111 1111
7F
128
1000 0000
80
255
1111 1111
FF
256
0001 0000 0000
100
1023
0011 1111 1111
3FF
65535
1111 1111 1111 1111
FFFF
Real-World Applications
Subnet mask 255.255.255.0: each octet in binary = 11111111.11111111.11111111.00000000 — the 24 ones give us /24 CIDR notation.
MAC address 00:1A:2B:3C:4D:5E: 6 hex pairs; total address space = 256⁶ ≈ 281 trillion.
ASCII 'A': decimal 65, binary 0100 0001, hex 41.
HTTPS port 443: hex 0x01BB = 443 decimal.
Common Mistakes
Treating hex letters as variables: in 0xFF, the F is the digit 15, not a variable. Always use the 0x prefix in code.
Missing leading zeros: in 8-bit formats, decimal 5 as a byte is 0000 0101, not 101.
Negative numbers: most systems use two's complement. −1 in 8 bits = 1111 1111, the same bit pattern as 255 unsigned.
Floating-point decimals: 0.1 has no exact binary representation (IEEE 754); expect small rounding errors.
Example: 255 decimal to hexadecimal
Input: 255 | From: Decimal | To: Hexadecimal
255 ÷ 16 = 15 remainder 15 (F)
15 ÷ 16 = 0 remainder 15 (F)
Read remainders bottom-up: FF
FF
Frequently asked questions
Why is hexadecimal used in programming?
Each hex digit represents exactly 4 bits (1 nibble), so one byte maps to just 2 hex digits (00 to FF). This makes memory addresses, color codes, CPU registers, and binary data far more readable than a long string of 0s and 1s.
How do I convert binary to hexadecimal without a calculator?
Group the binary digits into sets of 4 starting from the right. Convert each group to its hex equivalent. Example: 1010 1100 → A (1010) C (1100) → AC. If the total bits are not a multiple of 4, pad with leading zeros.
What do 0x, 0b, and 0o prefixes mean in code?
'0x' means hexadecimal (0xFF = 255). '0b' means binary (0b1010 = 10). '0o' or a leading zero in C means octal (0o77 = 63). These prefixes tell the compiler how to interpret the number literal.
How are negative numbers represented in binary?
The standard method is two's complement: flip all bits, then add 1. In 8 bits: +5 = 0000 0101, −5 = 1111 1011. Adding them gives 0000 0000 with the overflow bit discarded. This lets CPUs add and subtract using the same circuit.
Why does one byte go from 0 to 255?
A byte has 8 bits; each bit can be 0 or 1. Total combinations: 2⁸ = 256. Starting from 0, the maximum is 255. For 16 bits: 65,536 values (0–65,535). For 32 bits: 4,294,967,296 values (~4 billion).
How do I read a CSS hex color in decimal RGB?
Split the 6-character code into three pairs (RR GG BB) and convert each pair to decimal. Example: #FF6347 (Tomato) → FF=255, 63=99, 47=71 → rgb(255, 99, 71). Chrome DevTools shows all formats automatically when you click a color swatch.
What is the difference between octal and hexadecimal?
Octal (base 8) uses digits 0–7 and groups binary digits in sets of 3. Hex (base 16) uses 0–9 and A–F, grouping in sets of 4. Hex aligns perfectly with bytes (8 bits = 2 hex digits), making it far more common. Octal still appears in Unix file permissions (chmod 755).
How are floating-point numbers stored in binary?
Using the IEEE 754 standard: 1 sign bit + 8 exponent bits + 23 mantissa bits (single precision), or 64 bits total in double precision. The decimal 0.1 has no exact binary representation (it is a repeating fraction in base 2), which is why 0.1 + 0.2 equals 0.30000000000000004 in most programming languages.
Calculadora de matemática revisada por el equipo editorial de Hacé Cuentas, contrastada con IEEE 754-2019 — Standard for Floating-Point Arithmetic, según nuestra política editorial y metodología.
Updates
Última revisión: June 20, 2026. Los parámetros se verifican periódicamente con las fuentes citadas.
Privacy
Calculations run 100% in your browser. We do not store or transmit your data.
Limitations
Indicative results. For critical decisions, consult a professional.
📌 How to cite this calculator
Rodríguez, M. (2026). Convert Between Binary, Decimal, and Hexadecimal. Hacé Cuentas. https://hacecuentas.com/base-conversion-decimal-binary-hex
Contenido bajo licencia CC-BY 4.0 — reutilizable citando la fuente con enlace a Hacé Cuentas.
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