Base Converter
Convert numbers between binary, octal, decimal, hex, and any base from 2 to 36.
Base Converter is a free browser-based tool that instantly translates any integer between binary, octal, decimal, hexadecimal, and any custom base from 2 to 36. No upload or server request is needed — all conversion happens locally in JavaScript.
What is a Number Base Converter?
A number base converter translates integer values between different numeral systems. Every base uses a specific set of digits: binary (base 2) uses 0 and 1, octal (base 8) uses 0–7, decimal (base 10) uses 0–9, and hexadecimal (base 16) uses 0–9 and A–F. Bases 2 through 36 are supported — base 36 uses all digits 0–9 plus all letters A–Z.
How to Use
- Type or paste a number into the Number field.
- Select the base that number is already in — click a preset button (BIN, OCT, DEC, HEX, B32, B36) or enter a custom base in the Custom spinner.
- All six standard bases update instantly in the output cards below.
- Use the Convert to base field at the bottom to target any base from 2 to 36.
- Click Copy on any card to copy the raw value (without formatting spaces or commas) to your clipboard.
Supported Bases
| Base | Name | Digits | Common use |
|---|---|---|---|
| 2 | Binary | 0–1 | CPU instructions, bitfields, logic gates |
| 8 | Octal | 0–7 | Unix file permissions, legacy systems |
| 10 | Decimal | 0–9 | Everyday arithmetic |
| 16 | Hexadecimal | 0–9, A–F | Color codes, memory addresses, hashes |
| 32 | Base 32 | 0–9, A–V | Crockford encoding, TOTP secrets |
| 36 | Base 36 | 0–9, A–Z | URL shorteners, compact unique IDs |
FAQ
What is base conversion?
Base conversion is the process of expressing the same integer value in different numeral systems. Binary (base 2) uses digits 0 and 1, octal (base 8) uses 0–7, decimal (base 10) uses 0–9, and hexadecimal (base 16) uses 0–9 and A–F. Any integer can be represented in any base from 2 to 36.
Which characters are valid in each base?
Each base allows the first N characters from the sequence 0–9 and A–Z. Base 2 accepts only 0 and 1; base 16 accepts 0–9 and A–F; base 36 accepts all digits 0–9 and all letters A–Z. The tool shows the valid character range for the selected base and flags invalid digits immediately.
What is the maximum number this tool supports?
JavaScript represents numbers as 64-bit floating-point values and can safely handle integers up to 2^53 − 1, which equals 9,007,199,254,740,991 in decimal. Values larger than this boundary may lose precision. A warning is displayed when the entered value exceeds this limit.
What are Base 32 and Base 36 used for?
Base 32 (digits 0–9 and A–V) appears in Crockford encoding and TOTP authentication secret keys. Base 36 (digits 0–9 and A–Z) is case-insensitive and produces compact identifiers widely used in URL shorteners, unique ID systems, and serial numbers.
Why does the binary output show spaces?
Binary values are grouped into blocks of 4 bits (nibbles) separated by spaces for readability, matching the convention used in assembly programming and digital electronics. The Copy button copies the raw value without spaces so it is ready to paste directly into code.