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Convertitive

Hexadecimal to Octal Converter

FF (hex) = 377 (oct)

Convert hexadecimal numbers to octal numbers exactly, for any size. Convertitive parses your input as a BigInt — so 64-bit values, 256-bit hex strings, and even larger numbers round-trip without rounding. For quick reference: FF hex = 377 oct, and DEAD hex = 157255 oct.

377
Quick

How to convert hexadecimal numbers to octal numbers

  1. Enter a value

    Type a hexadecimal integer in the From field. Allowed characters: 0 through 9 and A through F.

  2. Read the octal result

    The To field updates as you type. For example, the hexadecimal value FF equals 377 in octal.

  3. Copy or share

    Use the copy button to grab the result. You can change either base from its dropdown without leaving the page.

Reference table

Fifty representative values. Every row is computed exactly by the same BigInt-based converter that powers the widget above.

Hexadecimal (hex)Octal (oct)
00
11
22
33
44
55
66
77
810
911
A12
B13
C14
D15
E16
F17
1020
1121
1222
1323
1424
1830
1F37
2040
2444
2A52
3060
3262
3F77
40100
64144
7F177
80200
C8310
FF377
100400
1F4764
1FF777
2001000
3E81750
3FF1777
4002000
8004000
100010000
200020000
400040000
8000100000
FFFF177777
10000200000
1000004000000

Frequently asked questions

How do I convert hexadecimal numbers to octal numbers?
Enter your hexadecimal value above. Convertitive parses it as an arbitrary-precision integer and reformats it in octal. The conversion is exact for any size — there's no float rounding.
What is FF in octal?
FF (hexadecimal) equals 377 in octal.
Are negative numbers supported?
No, only non-negative integers are supported for hexadecimal ↔ octal. Two's-complement encodings depend on a chosen bit-width, which this tool does not assume.
What's the largest number I can convert?
Any size. Convertitive uses JavaScript BigInt, which has no fixed upper bound — 256-bit hex strings, 512-bit and bigger all round-trip exactly.
How many bits does the result take?
An n-digit number in base 16 needs roughly 4.00 × n bits to store. The exact bit length equals ⌈log₂(value + 1)⌉.
Is hex case-sensitive?
No. You can type hex with letters in either case. Output is always uppercase (A–F).
Are conversion factors exact?
Yes. Base conversion is integer-to-integer; there are no factors, no rounding, no precision loss.
Why would I convert hexadecimal numbers to octal numbers?
Octal still shows up in Unix file permissions (chmod 755) and in some embedded systems. Converting from hexadecimal to octal is helpful when configuring file modes or working with legacy hardware documentation.

About hexadecimal and octal

Hexadecimal (base 16)

Hexadecimal (base 16) uses digits 0–9 plus the letters A–F to encode the values 10–15. It is the dominant compact notation for binary data: every two hex digits represent exactly one byte. Used universally for memory addresses, color codes (#RRGGBB), and cryptographic hashes.

Octal (base 8)

Octal (base 8) uses the digits 0 through 7. Each octal digit represents exactly three bits, which is why octal was widely used on early minicomputers and is still the conventional notation for Unix file-permission masks (e.g. 755).

Other base converters