Live 4-Way Sync
Type in any field — binary, octal, decimal, or hex — and the rest update instantly.
Developer Tool
Number Base Converter — Binary, Octal, Decimal & Hex
Convert between binary, octal, decimal, and hexadecimal live — type in any field and the others update instantly. Handles arbitrarily large numbers and custom bases 2–36.
- Live 4-Way Sync
- Huge Number Support
- Custom Base 2–36
- 100% Private
Convert Between Bases
Binary Base 2
Octal Base 8
Decimal Base 10
Hexadecimal Base 16
Custom Base Converter
Value
From Base
To Base
Result
Features
Every Base, One Tool
Convert instantly between the four bases developers use most, plus any custom base.
Huge Numbers
Powered by BigInt — correctly converts numbers far beyond standard 32/64-bit limits.
Custom Base 2–36
Convert to or from any base, not just the four common ones.
100% Private
Everything runs in your browser. Nothing is ever sent to a server.
How It Works
Convert in Seconds
- 1
Type a Number
Enter a value into any of the Binary, Octal, Decimal, or Hex fields.
- 2
See It Convert Live
The other three fields update instantly as you type.
- 3
Copy the Result
Click any copy icon to grab that format for your code or notes.
FAQ
Frequently Asked Questions
Type your binary number (using only 0s and 1s) into the Binary field. The Decimal field updates instantly with the equivalent base-10 value — no manual bit-by-bit calculation needed.
Type your number into the Decimal field. The Hex field updates live with the equivalent hexadecimal (base-16) value, using digits 0-9 and letters A-F.
Yes. This tool uses arbitrary-precision BigInt arithmetic internally, so it correctly converts numbers far larger than a standard 32-bit or 64-bit integer can hold — useful for cryptographic values, large IDs, or academic exercises.
Octal is base-8 notation, using digits 0-7. It's historically used in Unix file permissions (chmod), some older computing systems, and certain escape sequences in programming languages.
Yes. Use the Custom Base panel to convert any decimal number to any base from 2 to 36 (using digits 0-9 and letters A-Z), and back again.
Hexadecimal (base 16) needs 16 distinct digit symbols. After 0-9 are used up, the letters A-F represent the values 10 through 15, so every hex digit still corresponds to exactly one symbol.
What Is a Number Base?
A number base (or radix) defines how many unique digits are used to represent numbers and what each position's value multiplier is. Decimal (base 10) is the everyday system with digits 0-9. Computers work natively in binary (base 2) since transistors are either on or off. Hexadecimal (base 16) is a compact, human-friendlier way to write binary data — each hex digit represents exactly 4 bits. Octal (base 8) similarly maps cleanly to binary, with each digit representing 3 bits.
Quick Reference Table
| Decimal | Binary | Octal | Hex |
|---|---|---|---|
| 0 | 0 | 0 | 0 |
| 8 | 1000 | 10 | 8 |
| 15 | 1111 | 17 | F |
| 16 | 10000 | 20 | 10 |
| 255 | 11111111 | 377 | FF |
| 256 | 100000000 | 400 | 100 |
Why Hex Maps Cleanly to Binary
Because 16 is a power of 2 (2⁴), every group of exactly 4 binary digits corresponds to exactly one hex digit. That's why hex is the preferred shorthand for memory addresses, color codes, and byte values — 0xFF instantly tells you it's 8 bits, all set to 1, without counting.
Converting Manually: The Division-Remainder Method
To convert decimal to any other base by hand, repeatedly divide by the target base and record the remainders from last to first. For example, converting 12 to binary: 12÷2=6 r0, 6÷2=3 r0, 3÷2=1 r1, 1÷2=0 r1 — reading remainders bottom-to-top gives 1100. This tool automates that process instantly for any base.