Number Base Converter - Binary Octal Hex Decimal Online
Convert numbers between binary (base 2), octal (base 8), decimal (base 10), hexadecimal (base 16), and any custom base up to 36.
How to use this calculator
👉 Fill in the boxes below and your answer appears instantly — no maths needed, we do it all for you! 🎉
In plain English — what does this do?
📏 Some countries say ‘30 degrees’ and others say ‘86 degrees’ for the same weather! Some say ‘5 km’, others say ‘3 miles’. This tool swaps between them instantly so you always know what it means.
A number base (or radix) is the number of unique digits used to represent numbers in a positional numeral system. Decimal (base 10) uses digits 0–9, binary (base 2) uses 0–1, octal (base 8) uses 0–7, and hexadecimal (base 16) uses 0–9 and A–F. This converter handles all four standard bases plus any custom base from 2 to 36, using letters A–Z for digit values 10–35.
Base 2
Base 8
Base 10
Base 16
What is Number Base Converter - Binary Octal Hex Decimal Online?
A number base (or radix) is the number of unique digits used to represent numbers in a positional numeral system. Decimal (base 10) uses digits 0–9, binary (base 2) uses 0–1, octal (base 8) uses 0–7, and hexadecimal (base 16) uses 0–9 and A–F. This converter handles all four standard bases plus any custom base from 2 to 36, using letters A–Z for digit values 10–35.
How to use it
- 1️⃣ Enter a number in any of the four fields — binary, octal, decimal, or hexadecimal.
- 2️⃣ All other fields update instantly with the equivalent value.
- 3️⃣ Use the custom base fields to convert to/from any base between 2 and 36.
- 4️⃣ For hexadecimal, letters A–F are case-insensitive.
Formula
💡 See it in action — a real example
❓ Common questions
- Why do computers use binary?
- Binary maps directly to the two physical states of electronic components: on (1) and off (0). Logic gates, memory cells, and transistors all operate in these two states, making binary the natural language of digital hardware.
- What is hexadecimal used for?
- Hexadecimal is a compact representation of binary — each hex digit exactly represents 4 binary bits. It is used in programming, memory addresses, color codes (e.g. #FF5733), machine code, and debugging because it is far more readable than long binary strings.
- What is octal used for?
- Octal (base 8) groups binary into sets of 3 bits. It was commonly used in older computing systems and is still seen in Unix/Linux file permissions (e.g. chmod 755).
- What is the highest base this converter supports?
- Base 36, which uses digits 0–9 and letters A–Z. Base 36 is sometimes used for compact URL-safe identifiers and case-insensitive encoding.
- Can I convert negative numbers?
- This calculator converts unsigned (non-negative) integers. For negative numbers in binary, two's complement representation is required, which depends on the bit width and is beyond the scope of a simple base converter.