Number Converter

Convert between decimal, binary, octal, and hexadecimal number systems

Number System Conversion Calculator
Select a number system
Select a number system
Common Number Values
Number System Basics
Decimal (Base 10): 0-9
Binary (Base 2): 0-1
Octal (Base 8): 0-7
Hexadecimal (Base 16): 0-9, A-F
System Comparison
From System
Select a system
To System
Select a system
Quick Reference
Decimal Binary Octal Hexadecimal
0 0 0 0
1 1 1 1
2 10 2 2
3 11 3 3
4 100 4 4
5 101 5 5
6 110 6 6
7 111 7 7
8 1000 10 8
9 1001 11 9
10 1010 12 A
15 1111 17 F
16 10000 20 10
31 11111 37 1F
32 100000 40 20
63 111111 77 3F
64 1000000 100 40
127 1111111 177 7F
128 10000000 200 80
255 11111111 377 FF

Quick Number Conversions

11011000
D8
BIN HEX
73
163
HEX OCT
181
10110101
DEC BIN
183
10110111
DEC BIN
1010111
57
BIN HEX
11
13
DEC OCT
CB
203
HEX DEC
47
101111
DEC BIN
265
181
OCT DEC
140
1100000
OCT BIN

Number Converter | Decimal, Binary, Octal, Hexadecimal

Free online number system converter. Convert between decimal, binary, octal, and hexadecimal numbers instantly. Perfect for programming, math, and computer science.

Free Online Number System Converter

Our number converter tool allows you to instantly convert between different number systems. Whether you're a programmer converting decimal to binary, a student learning hexadecimal, or working with octal numbers, our tool provides accurate conversions in real-time.

Supported Number Systems

Decimal (Base 10)

  • Digits: 0-9
  • Symbol: DEC
  • Common Use: Everyday mathematics

Binary (Base 2)

  • Digits: 0-1
  • Symbol: BIN
  • Common Use: Computer systems

Octal (Base 8)

  • Digits: 0-7
  • Symbol: OCT
  • Common Use: Unix permissions

Hexadecimal (Base 16)

  • Digits: 0-9, A-F
  • Symbol: HEX
  • Common Use: Web colors, memory addresses

How to Use the Number Converter

  1. Enter the number - Type the number you want to convert in the "Convert From" field
  2. Select "From" system - Choose the number system you're converting from (e.g., Decimal)
  3. Select "To" system - Choose the number system you want to convert to (e.g., Binary)
  4. Get instant results - The converted number appears automatically
  5. Use quick values - Click on common values like "10 (DEC)" or "FF (HEX)" for quick conversion

Common Number Conversion Examples

Conversion Input Output
Decimal to Binary 10 (DEC) 1010 (BIN)
Binary to Decimal 1101 (BIN) 13 (DEC)
Decimal to Hexadecimal 255 (DEC) FF (HEX)
Hexadecimal to Decimal A5 (HEX) 165 (DEC)
Binary to Hexadecimal 11001100 (BIN) CC (HEX)

Practical Applications

💻 Programming & Computer Science

Convert between number systems for low-level programming, memory addressing, and digital electronics.

🎨 Web Design & Development

Convert color values between decimal RGB and hexadecimal color codes for CSS and design work.

📚 Mathematics & Education

Students can explore different number bases and understand positional numeral systems.

🔧 System Administration

Convert Unix file permissions between octal notation and binary representation.

Number System Fundamentals

What is a Number System?

A number system is a way to represent numbers using digits or symbols. The base (or radix) determines how many distinct digits are used. Our converter supports these four common bases:

Decimal (Base 10)
  • Uses digits 0-9
  • Most familiar system
  • Used in everyday life
  • Positional value increases by powers of 10
Binary (Base 2)
  • Uses digits 0 and 1
  • Foundation of digital systems
  • Used by computers internally
  • Positional value increases by powers of 2
Octal (Base 8)
  • Uses digits 0-7
  • Compact representation of binary
  • Used in Unix file permissions
  • Positional value increases by powers of 8
Hexadecimal (Base 16)
  • Uses digits 0-9 and A-F
  • Very compact representation
  • Used for memory addresses, colors
  • Positional value increases by powers of 16

💡 Conversion Tips

Quick Conversions
  • Decimal to Binary: Divide by 2 repeatedly, collect remainders
  • Binary to Decimal: Multiply each digit by 2position
  • Hex to Binary: Convert each hex digit to 4 binary digits
  • Binary to Hex: Group binary digits in 4s, convert each group
Remember These Common Values
DEC: 10
BIN: 1010
DEC: 255
HEX: FF
BIN: 11111111
HEX: FF
DEC: 16
HEX: 10

Start Converting Now!

Try our number converter with these common conversions: