Octal to Decimal

Tool processing runs in your browser — your pastes/files are not uploaded to our servers for processing. Ads (if shown) load separately and do not receive your tool inputs.Advertising · Details

Quick answer

To convert octal to decimal, multiply each digit by powers of 8 and add — for example 17 (octal) = 15. TryDevSnip's converter does it instantly and exactly, all in your browser.

Open octal → decimal converter

Octal to decimal chart

Octal	Decimal
1	1
7	7
10	8
17	15
20	16
77	63
100	64
777	511

Related: decimal to octal · hex to decimal · all bases

Worked example: 0o755

Every positional number system works the same way — each digit is multiplied by the base raised to its position, counting from zero on the right. For 0o755 in octal:

Digit	Place	Weight	Contribution
7	8²	64	448
5	8¹	8	40
5	8⁰	1	5
Total (decimal)			493

Written in decimal that is 493.

Quick reference

Decimal	octal	decimal
1	1	1
2	2	2
4	4	4
8	10	8
10	12	10
16	20	16
32	40	32
64	100	64
100	144	100
128	200	128
255	377	255
256	400	256

Things that trip people up

Prefixes are notation, not value. 0b1010,0o12, 0xA and 10 can all denote the same quantity. Strip the prefix before parsing, or tell the parser which base you meant.
Leading zeros can change the base. In several languages a leading0 historically meant octal, so 010 parsed as 8 rather than 10. Passing an explicit radix avoids the whole class of bug.
Hex letters are case-insensitive. 0xff and0xFF are the same number; only presentation differs.
Grouping is for humans. Binary is usually read in nibbles of four (1111 1111) because each nibble maps to exactly one hex digit — which is why hex is the usual shorthand for binary data.

Frequently asked questions

How do I convert octal to decimal?

Multiply each octal digit by powers of 8 (right to left) and add them. For example 17 (octal) = 1×8 + 7 = 15. Or paste it into the converter and read the decimal instantly.

What is 10 in octal in decimal?

10 (octal) is 8 in decimal — octal is base 8, so 10 means one group of eight.

Where is octal used?

Octal (base 8) is most common in Unix file permissions (e.g. chmod 755) and some legacy systems, because three bits map neatly to one octal digit.

Is my input uploaded?

No. TryDevSnip converts locally in your browser. Nothing you type is uploaded to our servers for processing.

Decimal	octal	decimal
1	1	1
2	2	2
4	4	4
8	10	8
10	12	10
16	20	16
32	40	32
64	100	64
100	144	100
128	200	128
255	377	255
256	400	256

Decimal	octal	decimal
1	1	1
2	2	2
4	4	4
8	10	8
10	12	10
16	20	16
32	40	32
64	100	64
100	144	100
128	200	128
255	377	255
256	400	256

Decimal	octal	decimal
1	1	1
2	2	2
4	4	4
8	10	8
10	12	10
16	20	16
32	40	32
64	100	64
100	144	100
128	200	128
255	377	255
256	400	256