Number Base Converter
Convert between binary, octal, decimal, hexadecimal and any base from 2 to 36 — instantly, in your browser.
255₁₀ = 11111111₂ = 377₈ = FF₁₆. Enter a value below, pick its base, and get every other base at once.
Reference table 0–15
| Decimal | Binary | Octal | Hex |
|---|---|---|---|
| 0 | 0000 | 0 | 0 |
| 1 | 0001 | 1 | 1 |
| 2 | 0010 | 2 | 2 |
| 3 | 0011 | 3 | 3 |
| 4 | 0100 | 4 | 4 |
| 5 | 0101 | 5 | 5 |
| 6 | 0110 | 6 | 6 |
| 7 | 0111 | 7 | 7 |
| 8 | 1000 | 10 | 8 |
| 9 | 1001 | 11 | 9 |
| 10 | 1010 | 12 | A |
| 11 | 1011 | 13 | B |
| 12 | 1100 | 14 | C |
| 13 | 1101 | 15 | D |
| 14 | 1110 | 16 | E |
| 15 | 1111 | 17 | F |
Frequently asked questions
How do I convert binary to decimal?
Multiply each digit by 2 raised to its position (right to left, starting at 0). For example 1011₂ = 1×8 + 0×4 + 1×2 + 1×1 = 11₁₀.
How do I convert decimal to binary?
Divide by 2 repeatedly and record the remainders; read them bottom-up. For example 11 → 11/2=5 r1, 5/2=2 r1, 2/2=1 r0, 1/2=0 r1 → 1011₂.
Why do programmers use hexadecimal?
One hex digit represents exactly 4 bits, so a byte is always two digits (00–FF). That makes hex the compact notation for addresses, colours (#FF5733) and binary data.
What do the 0x, 0b and 0o prefixes mean?
0x marks hexadecimal (0xFF = 255), 0b binary (0b1111 = 15), 0o octal (0o17 = 15). The tool recognises them automatically for the matching input base.
What is the largest supported base?
Base 36 — it uses the digits 0–9 and letters A–Z. It is popular for short URL identifiers because it packs the most information into readable characters.