How do you convert hex to decimal?

To convert hexadecimal to decimal, multiply each hex digit by 16 raised to the power of its position (starting from 0 on the right), then sum the results. Example: FF hex = (15 × 16¹) + (15 × 16⁰) = 240 + 15 = 255. Another example: 1A3B hex = (1 × 16³) + (10 × 16²) + (3 × 16¹) + (11 × 16⁰) = 4096 + 2560 + 48 + 11 = 6715.

What is hexadecimal (base 16)?

Hexadecimal (base 16) is a numeral system that uses 16 distinct symbols: the digits 0–9 and the letters A–F (where A=10, B=11, C=12, D=13, E=14, F=15). It is widely used in computing because one hexadecimal digit represents exactly 4 binary bits (a nibble), and two hex digits represent exactly one byte (8 bits). This makes hex a compact and readable way to express binary data, memory addresses, color codes, and machine code.

What does 0xFF mean in programming?

0xFF is a hexadecimal literal in programming languages including C, C++, Java, JavaScript, and Python. The '0x' prefix signals to the compiler that the following number is in base 16. FF in hex equals 255 in decimal. 0xFF is commonly used as a bitmask (binary 11111111) to isolate the lowest 8 bits of a value, as the maximum single-byte value, and as the 'fully opaque' or 'full intensity' value in color and image processing.

How are CSS hex colors structured?

CSS hex colors use the format #RRGGBB where RR is the red component, GG is the green component, and BB is the blue component — each a hexadecimal value from 00 (0 decimal) to FF (255 decimal). For example: #FF0000 is pure red (R=255, G=0, B=0), #00FF00 is pure green, #0000FF is pure blue, #FFFFFF is white (all 255), #000000 is black (all 0). A shorthand 3-digit format #RGB also exists where each digit is doubled: #F00 = #FF0000.

What is a nibble and a byte in hexadecimal?

A nibble is 4 binary bits, which can represent values 0–15, corresponding to a single hexadecimal digit (0–F). A byte is 8 binary bits, which can represent values 0–255, corresponding to exactly two hexadecimal digits (00–FF). This relationship is why hex is so useful in computing: one byte = two hex digits, making memory addresses and binary data much easier to read and write than long strings of 0s and 1s.

How do you convert hex to binary?

To convert hexadecimal to binary, replace each hex digit with its 4-bit binary equivalent. For example: F = 1111, A = 1010, 0 = 0000. So FA hex = 1111 1010 binary. This works because one hex digit always maps to exactly one nibble (4 bits). To convert binary to hex, group binary digits into groups of 4 from right to left and convert each group to its hex digit.

What are common hexadecimal values in computing?

Common hexadecimal values in computing include: 0x00 (0 — null byte), 0x0A (10 — newline character in ASCII), 0x20 (32 — space character in ASCII), 0x41 (65 — uppercase 'A' in ASCII), 0x61 (97 — lowercase 'a' in ASCII), 0xFF (255 — maximum byte value), 0x100 (256), 0xFFFF (65535 — maximum 16-bit value), 0xFFFFFF (16777215 — maximum 24-bit value, used in RGB colors), 0xFFFFFFFF (4294967295 — maximum 32-bit unsigned integer).

Decimal to Hex Converter - Free Online Tool

Input

Uppercase A–F Add 0x prefix Pad to even bytes Group pairs (XX XX)

Hexadecimal Result

255

Decimal

Hex

Hex digits

Bytes

All bases

Decimal (Base 10)

255

Hex (Base 16)

Binary (Base 2)

11111111

Octal (Base 8)

377

Quick Samples

CSS colors:

History

No conversions yet.

Hex Digit Reference

Dec	Hex	Bin

Tips

Divide by 16 repeatedly, map remainders 0–9/A–F, read bottom-to-top.

CSS colors are 6-digit hex: #RRGGBB . Each pair = 0–255.

0x prefix marks hex literals in C, Java, JavaScript, Python.

One hex digit = 4 bits (nibble). Two hex digits = 1 byte (8 bits).

FF = 255 decimal = 11111111 binary = the maximum byte value.

Decimal to Hex Conversion Table — 0 to 255

This is the complete reference table for all decimal values 0 to 255 with their hexadecimal, binary, and octal equivalents. This range covers the full single-byte value space — the most commonly encountered range in color codes, ASCII, networking, and low-level programming.

Decimal	Hex	Binary	Octal	Decimal	Hex	Binary	Octal

Use the converter above for values beyond 255 or for reverse conversion (hex → decimal).

How Hexadecimal (Base 16) Works — Complete Explanation

Hexadecimal is a positional numeral system with a base of 16. Like decimal (base 10) uses ten digits (0–9), hexadecimal uses sixteen symbols: the digits 0 through 9 and the letters A through F, where A represents 10, B represents 11, C represents 12, D represents 13, E represents 14, and F represents 15.

Positional Value in Hexadecimal

In any positional number system, each digit's value is the digit multiplied by the base raised to the power of its position (counting from 0 on the right). In hexadecimal, each position is a power of 16:

Position	Power of 16	Value	Example digit	Contribution
Rightmost (0)	16⁰	1	B (=11)	11 × 1 = 11
Second from right (1)	16¹	16	A (=10)	10 × 16 = 160
Third from right (2)	16²	256	3	3 × 256 = 768
Fourth from right (3)	16³	4096	1	1 × 4096 = 4096

So 13AB in hex = 4096 + 768 + 160 + 11 = 5035 in decimal .

Why Computers Use Hexadecimal

Computers operate in binary (base 2), using only 0s and 1s. Binary numbers become very long very quickly — the decimal number 255 requires 8 binary digits ( 11111111 ). Hexadecimal provides a compact shorthand: every 4 binary bits map to exactly one hex digit, and every 8 bits (1 byte) map to exactly two hex digits. This makes hex the natural language for expressing memory addresses, machine code, color values, cryptographic hashes, and network addresses.

The Relationship Between Hex and Binary

Hex digit	Decimal value	4-bit binary
0	0	0000
1	1	0001
2	2	0010
3	3	0011
4	4	0100
5	5	0101
6	6	0110
7	7	0111
8	8	1000
9	9	1001
A	10	1010
B	11	1011
C	12	1100
D	13	1101
E	14	1110
F	15	1111

How to Convert Decimal to Hex — Step-by-Step Method

The standard method for converting a decimal integer to hexadecimal is repeated division by 16 . Here are three worked examples at different scales.

Example 1: Convert 255 to Hex

255 ÷ 16 = 15, remainder 15 → F
15 ÷ 16 = 0, remainder 15 → F
Reading remainders bottom-to-top: FF
Result: 255 decimal = FF hexadecimal

Example 2: Convert 4096 to Hex

4096 ÷ 16 = 256, remainder 0 → 0
256 ÷ 16 = 16, remainder 0 → 0
16 ÷ 16 = 1, remainder 0 → 0
1 ÷ 16 = 0, remainder 1 → 1
Reading bottom-to-top: 1000
Result: 4096 decimal = 1000 hexadecimal

Example 3: Convert 16711680 to Hex (Red CSS color)

16711680 ÷ 16 = 1044480, remainder 0 → 0
1044480 ÷ 16 = 65280, remainder 0 → 0
65280 ÷ 16 = 4080, remainder 0 → 0
4080 ÷ 16 = 255, remainder 0 → 0
255 ÷ 16 = 15, remainder 15 → F
15 ÷ 16 = 0, remainder 15 → F
Reading bottom-to-top: FF0000
Result: 16711680 decimal = FF0000 hex (pure red in CSS)

Converting Hex Back to Decimal

Multiply each hex digit by 16 raised to the power of its position and sum the results:

FF = (F × 16¹) + (F × 16⁰) = (15 × 16) + (15 × 1) = 240 + 15 = 255
1A3B = (1 × 4096) + (A × 256) + (3 × 16) + (B × 1) = 4096 + 2560 + 48 + 11 = 6715
FFFFFF = (F × 65536×15) + ... = 16777215

Where Hexadecimal Is Used — Real-World Applications

Hexadecimal is used throughout computing, networking, graphics, and software development. Understanding hex is essential for any programmer, sysadmin, or digital designer.

🎨 CSS & HTML Colors

All CSS hex colors follow the #RRGGBB format. Each two-digit hex pair represents one color channel (0–255). Example: #1A2B3C = R:26, G:43, B:60. Shorthand #RGB is also valid.

💾 Memory Addresses

CPU memory addresses are expressed in hex in debuggers, disassemblers, and system logs. Example: 0x7FFE4A00 is a typical stack address. Hex is standard in GDB, LLDB, WinDbg, and all memory profilers.

🖥️ Programming Literals

Hex literals appear in code across all major languages. In C/C++/Java/JavaScript/Python: 0xFF , 0x1A3B . They're used for bitmasks, flags, hardware registers, and protocol constants.

🔐 Cryptographic Hashes

SHA-256, MD5, and all common hash algorithms output hex strings. A SHA-256 hash is 64 hex characters (256 bits = 32 bytes = 64 hex digits). Example: a665a45920422f9d417e4867efdc4fb8 .

🌐 IP & MAC Addresses

IPv6 addresses are written in hex groups: 2001:0db8:85a3:0000 . MAC (Ethernet) addresses are 6 bytes in hex: 00:1A:2B:3C:4D:5E . IPv4 is sometimes expressed as a single hex value.

📁 File Formats & Magic Bytes

Every binary file format begins with a "magic number" in hex. JPEG files start with FF D8 FF , PNG with 89 50 4E 47 , PDF with 25 50 44 46 . Hex editors use these to identify file types.

🔧 Assembly & Machine Code

CPU opcodes and machine code are written in hex. x86 assembly instruction encodings, ARM opcodes, and microcontroller register values are all expressed as hex bytes in datasheets and firmware.

🎮 Game Development

Game engines store color values, flags, item IDs, and save file data in hex. Cheat codes and memory editors work directly with hex addresses and values in game memory.

Comparing Number Systems — Decimal, Hex, Binary, Octal

Computers use multiple number systems for different purposes. Here is a comparison of the four most important bases used in computing.

Property	Decimal (Base 10)	Hexadecimal (Base 16)	Binary (Base 2)	Octal (Base 8)
Digits used	0–9	0–9, A–F	0, 1	0–7
Base	10	16	2	8
Bits per digit	~3.32 bits	4 bits (exact)	1 bit (exact)	3 bits (exact)
Digits to represent 255	3 (255)	2 (FF)	8 (11111111)	3 (377)
Prefix in code	none	0x	0b	0 or 0o
Common uses	Everyday numbers, human I/O	Colors, addresses, hashes	CPU logic, bitwise ops	Unix permissions, legacy

Important Hex Boundary Values

Hex Value	Decimal	Significance
0x00	0	Null byte / minimum single byte value
0x0A	10	ASCII newline character (LF)
0x1F	31	Last ASCII control character
0x20	32	ASCII space character
0x41	65	ASCII uppercase 'A'
0x61	97	ASCII lowercase 'a'
0x7F	127	ASCII DEL character / max 7-bit value
0xFF	255	Maximum single-byte value
0x100	256	First value requiring 2 bytes (9 bits)
0xFFFF	65535	Maximum 16-bit unsigned integer
0xFFFFFF	16777215	Maximum 24-bit value / max RGB color
0xFFFFFFFF	4294967295	Maximum 32-bit unsigned integer

Frequently Asked Questions — Decimal to Hex Converter

Answers to the most common questions about hexadecimal numbers, conversion methods, and this tool.

How do you convert decimal to hexadecimal by hand?

Divide the decimal number by 16. Record the remainder and map it to its hex digit (0–9 stay as digits; 10=A, 11=B, 12=C, 13=D, 14=E, 15=F). Take the quotient and divide again by 16. Repeat until the quotient is 0. Read the hex digits you collected from bottom to top — that is your hexadecimal result. Example: 255 ÷ 16 = 15 R 15(F) → 15 ÷ 16 = 0 R 15(F) → reading bottom-to-top: FF.

What is 255 in hexadecimal?

255 in decimal is FF in hexadecimal. This is because 255 = (15 × 16) + 15, and 15 maps to F in hex. FF is the maximum value of a single byte (8 bits = 11111111 in binary). It appears as the maximum color channel value in CSS (#FFFFFF = white), as a bitmask 0xFF in programming, and as the broadcast byte in IPv4 (255.255.255.255).

What does the 0x prefix mean in programming?

The

0x

prefix is a convention used in C, C++, Java, JavaScript, Python, and many other programming languages to indicate that the following number is in hexadecimal (base 16). For example,


        0xFF

is the hex literal for 255, and


        0x1A3B

is the hex literal for 6715. Without the prefix, the compiler would interpret the value as decimal. Python also accepts

0b

for binary and

0o

for octal.

How do CSS hex colors work?

CSS hex colors follow the format


        #RRGGBB

where RR is the red channel, GG is green, and BB is blue — each a two-digit hex value from 00 (decimal 0) to FF (decimal 255). For example:


        #FF0000

is pure red (R=255, G=0, B=0),


        #00FF00

is pure green,


        #0000FF

is pure blue,


        #FFFFFF

is white,


        #000000

is black. A 4-digit


        #RGBA

and 8-digit


        #RRGGBBAA

format also exists with an alpha transparency channel. The 3-digit shorthand


        #RGB

doubles each digit:


        #F00


        #FF0000

What is a nibble and how does it relate to hex?

A nibble is exactly 4 binary bits. It can represent 16 distinct values (0 to 15), which maps perfectly to the 16 hexadecimal digits (0–F). This 1-to-1 relationship is why hex is so useful for expressing binary data: one hex digit = one nibble = 4 bits. Two hex digits = one byte = 8 bits. A 32-bit integer requires 8 hex digits; a 64-bit integer requires 16 hex digits.

Can I convert hex to binary directly without going through decimal?

Yes. Because one hex digit = exactly 4 binary bits, you can convert hex to binary directly by substituting each hex digit with its 4-bit binary equivalent without any arithmetic. For example:

= 1011,

= 1010, so

BA

hex =

10111010

binary. Similarly, to go from binary to hex, group the binary digits into 4-bit groups from right to left and convert each group to its hex digit.

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