Convert Hexadecimal to Octal

Convert hexadecimal to octal instantly — free online hex to octal number converter.

About

About the Hexadecimal to Octal Converter

Hex and octal rarely need to talk to each other directly, but it does come up when older octal notation — like a legacy permission code — needs to be cross-checked against a hex value from newer documentation or code.

There's no digit-for-digit shortcut between hex and octal, because one hex digit is 4 bits and one octal digit is 3. The hand method goes through binary: expand each hex digit into 4 bits, then regroup from the right in threes. 1ED is 0001 1110 1101, which regroups as 111 101 101 — octal 755.

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Guide

Using the Hexadecimal to Octal Converter

  1. 1

    Step 1

    Hexadecimal is already selected below as the input base.

  2. 2

    Step 2

    Type your hex digits (0-9, A-F) into the value box.

  3. 3

    Step 3

    The result table fills in instantly — the octal value sits alongside binary, decimal and hex all at once.

  4. 4

    Step 4

    For a quick manual check, expand each hex digit to 4 bits, then regroup the whole binary string into groups of 3 bits from the right to read off the octal digits.

  • Converts hex to octal as you type, without the binary detour
  • Accepts an optional 0x prefix and either letter case
  • Shows the binary form too, so you can follow the regrouping yourself
  • Shows the value in binary, octal, decimal, hexadecimal and base 36 at once, plus any custom base from 2 to 36
  • Exact for whole numbers up to 9,007,199,254,740,991, and tells you when a number is too large
  • Runs entirely in your browser — free, with no sign-up and no limit

Linux administrators

Admins compare a permission mode shown in hex by a tool with the octal chmod expects.

Developers porting old code

Developers translate octal constants and escapes into the hex used in newer code, or back.

Students

Students check conversions that go through binary as an intermediate step.

Retro-computing fans

Hobbyists move values between octal-era documentation and modern hex tools.

Popular base conversions

Binary Octal Binary Decimal Binary Hexadecimal Octal Binary Octal Decimal Octal Hexadecimal Decimal Binary Decimal Octal Decimal Hexadecimal Hexadecimal Binary Hexadecimal Decimal

Examples

Hexadecimal to Octal examples

4 worked examples

01

A full byte, FF

Hex FF (255 in decimal) converts to octal 377 — computed by going through decimal or binary as a middle step since hex and octal don't share a common bit grouping.

02

A smaller value, 1F

Hex 1F (31 in decimal) converts to octal 37.

03

A round number, 100

Hex 100 (256 in decimal) converts to octal 400.

04

Full permissions

1FF converts to 777 in octal — read, write and execute for everyone.

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FAQ

Frequently asked questions

Quick answers to common questions about the Hexadecimal to Octal Converter.

How do I convert hex to octal?

Type your hex value above, with hexadecimal selected as the input base. The octal value appears instantly in the results table — nothing is uploaded anywhere.

How do you convert hex to octal by hand?

There's no direct digit-for-digit shortcut between hex and octal, since 16 and 8 aren't powers of a shared base in the same way — expand the hex to binary first, then regroup the binary into 3-bit chunks to read off the octal digits.

Why isn't there a quick hex-to-octal shortcut like there is for hex-to-binary?

Hex digits map cleanly to groups of 4 bits and octal digits to groups of 3 bits, but 4 and 3 don't share a common grouping — so converting between them means going through binary (or decimal) as a middle step.

Is this hex to octal converter free?

Yes. It's free, with no sign-up and no limit on how many numbers you convert.

Can I convert octal back to hex?

Yes — the same converter works in both directions. Select octal as the input base instead, or use the dedicated octal to hex converter page.

How large a hex value can I convert?

Up to 9,007,199,254,740,991 in decimal terms — beyond that the conversion won't be exact, and the tool will tell you so.

Can I convert a hex value with a 0x prefix?

Yes. The 0x is removed before converting, so 0x1FF and 1FF both give 777.

What does hex 1ED become in octal?

755 — the familiar chmod permission. Hex 1ED is 493 in decimal, which is written 755 in octal.

Are hex letters case-sensitive here?

No. 1ed, 1ED and 1Ed are all read as the same value.

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