Binary to Octal Converter

Type a Binary number and get Octal instantly — plus every other base at the same time.

From To Mode

Number

Every base updates as you type; click bits to toggle them. Digit separators (_, spaces) are allowed. In two's complement mode the binary/octal/hex rows show the bit pattern and the decimal row shows the signed value. Choose Text to convert ASCII/UTF-8 text to bytes in any base — or bytes back to text.

How to convert Binary to Octal

Binary and octal line up perfectly: every group of 3 bits is exactly one octal digit. Pad the binary number with leading zeros to a multiple of 3, split it into groups of 3 starting from the right, and translate each group using the table below.

Worked example

Convert 101101 (binary) to octal:

Start with binary 101101; pad to a multiple of 3 bits: 101 101
101 → 5
101 → 5
Result: 55

So 101101 in binary is 55 in octal.

Binary to Octal conversion table

Binary	Octal
0	0
1	1
10	2
11	3
100	4
101	5
110	6
111	7
1000	10
1001	11
1010	12
1011	13
1100	14
1101	15
1110	16
1111	17

Frequently asked questions

Can this handle numbers larger than 64 bits?: Yes. Conversion runs on arbitrary-precision integers, so numbers of any length convert exactly. Many online converters silently lose precision above 2⁵³ (about 16 decimal digits) — this one doesn't.
How do I convert negative numbers?: A leading minus sign works in every base. For the bit-pattern view programmers usually want, switch the mode to two's complement at 8, 16, 32, or 64 bits — then binary, octal, and hex show the bit pattern while decimal shows the signed value.
Can I convert the other way, or to other bases?: Use the Octal to Binary converter, or just change the From/To dropdowns above — every common base is shown at once anyway, and a Text mode converts ASCII to bytes and back.

Need arithmetic rather than conversion — adding hex numbers, shifting bits, masking? Use the programmer's calculator.