Number Base Converter
Convert between binary, octal, decimal, hexadecimal, and any base 2–36. 100% client-side — your data never leaves your browser.
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About Number Base Converter
Computers work in binary (base 2), but humans prefer decimal (base 10). Between these extremes, developers frequently encounter octal (base 8) for Unix file permissions, hexadecimal (base 16) for memory addresses and color codes, and occasionally base 32 or base 64 for encoding schemes. A number base converter lets you translate a value from any of these systems to any other instantly. This tool supports bases 2 through 36, showing the same numeric value in binary, octal, decimal, hexadecimal, and your chosen base — plus an ASCII preview for byte-sized values.
How It Works
- Enter a number in the input box.
- Select the input base (2, 8, 10, 16, or a custom base 2–36).
- See the same value converted to binary, octal, decimal, and hexadecimal simultaneously.
- Use the custom base selector to convert to any base from 2 to 36 (digits 0–9 and A–Z).
✨ Key Features
- ✓Convert between binary (2), octal (8), decimal (10), and hexadecimal (16)
- ✓Custom base conversion from 2 to 36
- ✓Live conversion as you type
- ✓Uppercase and lowercase input accepted
- ✓ASCII character preview for byte values (0–255)
- ✓Invalid input detection with helpful messages
- ✓One-click copy for any output field
- ✓100% client-side — no data sent to any server
🎯 Common Use Cases
- →Converting memory addresses between hex and decimal
- →Reading or writing Unix file permissions in octal
- →Debugging bitwise operations in binary
- →Translating RGB color codes between hex and decimal
- →Working with binary protocols and packet inspection
- →Understanding CPU registers and assembly language
- →Base64 and Base32 encoding/decoding internals
- →Converting Unicode code points between hex and decimal
💡 Advanced Tips & Pro Insights
- ▸Hexadecimal uses digits 0–9 and letters A–F to represent values 10–15. Binary uses only 0 and 1. Octal uses 0–7.
- ▸Each hex digit represents 4 binary bits (a nibble). Two hex digits = 1 byte. This is why hex is preferred for byte-level work.
- ▸In many languages, hex literals are prefixed with 0x (0xFF), binary with 0b (0b1111), and octal with 0o (0o755).
- ▸The maximum value for a single byte is 255 in decimal, FF in hex, or 11111111 in binary.
- ▸For bases above 16, letters continue: A=10, B=11, ..., Z=35. This lets you represent up to base 36.
Frequently Asked Questions
Is this number base converter free?▾
Yes, this number base converter is completely free with no signup, registration, or usage limits.
Is my data safe?▾
Yes, 100% safe. All conversions happen in your browser. Nothing is sent to any server.
What is a number base?▾
A number base (or radix) is the number of unique digits used to represent numbers. Binary uses 2 digits (0, 1), decimal uses 10 (0–9), hexadecimal uses 16 (0–9 and A–F). Different bases are useful in different contexts.
Why do programmers use hexadecimal?▾
Hexadecimal is compact and maps cleanly to binary: each hex digit represents exactly 4 binary bits. One byte (8 bits) is exactly two hex digits, making hex ideal for reading and writing byte-level data like memory addresses and color codes.
What is octal used for?▾
Octal (base 8) is commonly used for Unix/Linux file permissions (e.g. 755 or 644). Each octal digit represents exactly 3 binary bits, which maps cleanly to the 9 permission bits of Unix files.
How do I convert a hex value with 0x prefix?▾
Just remove the 0x prefix before entering the value. For example, 0xFF becomes FF. This tool accepts lowercase too (0xff → ff).
What is the maximum base this tool supports?▾
This tool supports bases from 2 to 36. Base 36 uses all digits 0–9 and letters A–Z (A=10, B=11, ..., Z=35).
Can I convert negative numbers?▾
Yes, negative numbers are supported — just prefix the input with a minus sign (-). The output will also be negative in all bases.