A number base converter instantly converts numbers between binary, octal, decimal, and hexadecimal, showing all bases simultaneously. Whether you are a computer science student learning number systems, a developer debugging hex values, or a networking professional working with IP addresses, this free online base converter gives you instant, accurate results. No signup required.
Try the Free Online Number Base Converter
How to Use Number Base Converter — Step by Step
Step 1: Select your input base
Choose whether your number is in decimal (base 10), binary (base 2), octal (base 8), or hexadecimal (base 16). This tells the tool how to interpret your input.
Step 2: Enter your number
Type or paste your number into the input box. The tool validates the input against the selected base and shows an error if invalid characters are detected.Step 3: See all conversions
The tool instantly displays the equivalent value in all four number bases. Each result updates in real time as you type, with no buttons to press.Step 4: Copy and use
Each output field can be copied individually. Use the values in your code, configuration, or documentation as needed.
Real-World Examples
Color Codes: You see #FF5733 in CSS and want to know the decimal RGB values. Enter FF5733 in hex mode and instantly see decimal 16734003, with binary and octal also displayed.
Networking: You are calculating a subnet mask. Enter the decimal value 255 and see it equals 11111111 in binary, 377 in octal, and FF in hex.
CS Homework: Your professor asks you to convert decimal 42 to binary. Enter 42 and instantly see 101010 in binary, 52 in octal, and 2A in hex.
Memory Addresses: You are debugging a C program and see a pointer at 0x7FFC. Enter in hex mode to see decimal 32764, binary 111111111111100, and octal 77774.
File Permissions: You need to set chmod 755. Enter 755 in octal to see binary 111101101 and hex 1ED — useful for understanding the bit flags.
Features
- Converts between binary, octal, decimal, and hexadecimal simultaneously
- Real-time conversion as you type, with no buttons required
- Input validation shows errors for invalid characters per base
- 100% private — all processing happens in your browser
- Handles numbers up to JavaScript's safe integer limit
- Free forever with instant, accurate results
Tips & Best Practices
- Know your prefixes: Binary often uses 0b, octal 0o, hex 0x. The tool accepts numbers without prefixes — just select the input base.
- Watch for case in hex: The tool accepts both uppercase (A-F) and lowercase (a-f) hex digits. Output is uppercase by convention.
- Use for color conversion: Hex color #RRGGBB splits into three hex bytes. Convert each to decimal for RGB values (0-255 each).
- Verify subnet masks: A /24 mask is 255.255.255.0. Convert 255 to binary (11111111) to see the 24 network bits.
- Check safe integer limit: JavaScript's MAX_SAFE_INTEGER is 9,007,199,254,740,991 (2^53-1). Beyond this, precision is lost.
- Combine with Text to Binary: Use Text to Binary for character-level encoding, this tool for numeric base conversion.
Common Use Cases
Computer Science Students
Learn and verify number base conversions for coursework, exams, and understanding how computers represent data.
Software Developers
Convert between hex color codes, memory addresses, and decimal values during debugging and development.
Network Engineers
Work with IP addresses, subnet masks, and MAC addresses that require conversion between decimal and hexadecimal.
Embedded Systems Engineers
Convert register values, memory maps, and peripheral addresses between bases during firmware development.
Frequently Asked Questions
Q: What is a number base?
A: A number base (or radix) is the number of unique digits used to represent values. Binary uses base 2 (0-1), octal uses base 8 (0-7), decimal uses base 10 (0-9), and hexadecimal uses base 16 (0-9, A-F).
Q: What is hexadecimal used for?
A: Hexadecimal is commonly used in web development for color codes (#FF5733), memory addresses, assembly language, and representing binary data in a compact form.
Q: How do I convert decimal to binary?
A: Enter your decimal number, select Decimal (10) as the input base, and the tool instantly shows the binary, octal, and hexadecimal equivalents.
Q: Is my data kept private?
A: Yes. All conversion happens locally in your browser. No data is sent to any server.
Q: What is the maximum number I can convert?
A: The tool handles numbers up to Number.MAX_SAFE_INTEGER (9,007,199,254,740,991) in JavaScript, which covers virtually all practical use cases.Q: Does it handle negative numbers?
A: No. The tool is designed for unsigned integers. For negative numbers, convert the absolute value and apply the sign manually.
Q: Can it convert fractional numbers?
A: No. This tool only handles integers. For floating-point conversion, use a specialized IEEE 754 converter.
Q: Why does hex output use uppercase letters?
A: Uppercase (A-F) is the conventional representation for hexadecimal in most programming contexts and documentation.
Q: What's the difference between this and Text to Binary?
A: Number Base Converter works on numeric values (42 → 101010). Text to Binary converts text characters to their 8-bit ASCII/UTF-8 binary representation (\"A\" → 01000001). Different use cases.
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