Hex to Octal Converter
Convert hexadecimal to octal instantly with exact integer conversion. Enter any valid hex number to get its base-8 result, binary bridge, digit counts, verified examples, and conversion tables.
What Is a Hex to Octal Converter?
A hex to octal converter changes a value from the hexadecimal number system (base 16) into its equivalent octal number system (base 8).
Hexadecimal uses digits 0 through 9 and letters A through F. Octal uses only digits 0 through 7.
Both systems connect naturally to binary. One hexadecimal digit maps to exactly four binary bits, while one octal digit maps to exactly three bits. Binary therefore provides a convenient bridge between the two bases.
Hexadecimal — Base 16
One hex digit corresponds to four binary bits.
Octal — Base 8
One octal digit corresponds to three binary bits.
How to Use the Hex to Octal Converter
Type a value such as 2F. Lowercase characters and the
optional 0x prefix are accepted.
BinaryCon converts the hexadecimal value exactly into base 8.
For shorter inputs, the calculator shows the equivalent binary value and how it is regrouped into 3-bit octal groups.
The result card displays the number of hexadecimal digits, octal digits, and significant binary bits.
Use the output in programming, system administration, computer science, digital logic, or another BinaryCon converter.
How Hex to Octal Conversion Works
The easiest manual method is usually to convert the hexadecimal number into binary first and then regroup the binary digits into groups of three from the right.
Join the binary groups
Regroup from the right into 3 bits
Convert each 3-bit group to octal
Worked Example: Convert Hex 2F to Octal
Start with hexadecimal 2F.
F → 1111 Join the groups: 00101111 Regroup from the right into sets of three: 00 101 111 Pad the leftmost group: 000 101 111 Convert each group: 000 → 0
101 → 5
111 → 7 Ignore the insignificant leading octal zero: 57 Therefore: 2F₁₆ = 57₈
Example: Convert Hex FF to Octal
F → 1111
FF → 11111111 Group from the right in threes: 11 111 111 Pad the left group: 011 111 111 Convert: 011 → 3
111 → 7
111 → 7 Therefore: FF₁₆ = 377₈ Both values equal decimal 255.
Hex to Octal Conversion Table
| Hex | Octal | Decimal |
|---|---|---|
0 | 0 | 0 |
7 | 7 | 7 |
8 | 10 | 8 |
A | 12 | 10 |
F | 17 | 15 |
10 | 20 | 16 |
1F | 37 | 31 |
20 | 40 | 32 |
2D | 55 | 45 |
2F | 57 | 47 |
3F | 77 | 63 |
40 | 100 | 64 |
7F | 177 | 127 |
80 | 200 | 128 |
FF | 377 | 255 |
100 | 400 | 256 |
1FF | 777 | 511 |
Hex to Binary Reference
| Hex | Binary | Hex | Binary |
|---|---|---|---|
| 0 | 0000 | 8 | 1000 |
| 1 | 0001 | 9 | 1001 |
| 2 | 0010 | A | 1010 |
| 3 | 0011 | B | 1011 |
| 4 | 0100 | C | 1100 |
| 5 | 0101 | D | 1101 |
| 6 | 0110 | E | 1110 |
| 7 | 0111 | F | 1111 |
Binary to Octal Reference
| Binary | Octal |
|---|---|
000 | 0 |
001 | 1 |
010 | 2 |
011 | 3 |
100 | 4 |
101 | 5 |
110 | 6 |
111 | 7 |
Why Hex A Equals Octal 12
Hexadecimal A represents decimal 10.
Why Hex FF Equals Octal 377
Hex FF is a common benchmark because it represents one full unsigned byte.
Can Hex Be Converted Directly to Octal?
Yes. The exact integer can be converted mathematically from base 16 to base 8, but for manual work the binary bridge is usually easier to understand.
Another valid path is:
Both methods produce the same result. BinaryCon calculates the result exactly while also showing the binary grouping method for educational clarity.
Why Padding Is Sometimes Needed
A binary value produced from hexadecimal naturally comes in groups of four. Octal requires groups of three. Those group sizes do not always align.
For example:
Adding zeros only at the far left does not change an unsigned integer’s value.
Hex, Octal, Binary, and Decimal Comparison
| Decimal | Binary | Octal | Hex |
|---|---|---|---|
| 8 | 1000 | 10 | 8 |
| 10 | 1010 | 12 | A |
| 15 | 1111 | 17 | F |
| 16 | 10000 | 20 | 10 |
| 45 | 101101 | 55 | 2D |
| 47 | 101111 | 57 | 2F |
| 255 | 11111111 | 377 | FF |
| 511 | 111111111 | 777 | 1FF |
Where Hex to Octal Conversion Is Useful
Programming
Convert hexadecimal constants or machine values when an application, tool, or file format expects octal notation.
Unix and systems work
Hex values may need to be compared with octal-style permissions, modes, masks, or system documentation.
Digital logic
Converting through binary helps compare 4-bit hexadecimal groupings with 3-bit octal groupings.
Computer science education
Hex-to-octal conversion demonstrates how different positional bases can share the same underlying binary value.
Common Hex to Octal Conversion Mistakes
When converting to octal, form 3-bit groups starting from the rightmost bit.
Four-bit groups are hexadecimal. Octal requires exactly three binary bits per digit.
A, B, C, D, E, and F represent decimal values 10 through 15.
If padding is required, zeros are added only on the far left of the unsigned binary value, never on the right.
Related BinaryCon Tools
Reverse this conversion or continue working with hexadecimal, octal, binary, decimal, and ASCII values.
Hex to Octal Converter FAQs
How do you convert hexadecimal to octal?
Convert every hex digit to four binary bits, join the groups, then regroup the complete binary number into groups of three from the right. Pad the leftmost group with zeros if needed and convert each 3-bit group to one octal digit.
What is hex A in octal?
Hexadecimal A equals decimal 10, which is octal 12.
What is hex F in octal?
Hexadecimal F equals decimal 15, which is octal 17.
What is hex 2F in octal?
Hex 2F converts to binary 00101111. Regrouping into
three bits gives 000 101 111, which becomes octal
57.
What is hex 2D in octal?
Hexadecimal 2D equals decimal 45, which is octal 55.
What is hex FF in octal?
Hexadecimal FF equals decimal 255 and octal 377.
What is hex 1FF in octal?
Hexadecimal 1FF equals decimal 511, which is octal 777.
Why is binary useful when converting hex to octal?
Every hexadecimal digit maps to four binary bits, while every octal digit maps to three bits. Binary therefore allows exact regrouping between the two systems without approximation.
Can hex be converted to octal without decimal?
Yes. The binary regrouping method converts directly from hexadecimal to octal without using decimal as an intermediate value.
Does this converter accept 0x-prefixed hexadecimal values?
Yes. Values such as 0xFF are accepted. The prefix is removed
before the hexadecimal digits are converted.
Can I use lowercase hex letters?
Yes. Hexadecimal notation is normally case-insensitive, so
ff and FF have the same value.
Can this converter handle very large hexadecimal integers?
Yes. The conversion works using direct hexadecimal-to-binary mapping and string regrouping, avoiding ordinary floating-point precision limits.
Is hex-to-octal conversion exact?
Yes. Integer conversion between hexadecimal, binary, and octal is exact. No rounding or approximation is required.
Why are zeros sometimes added before binary grouping?
Octal needs groups of exactly three bits. If the leftmost group contains fewer than three bits, zeros are added on the left only to complete the group. Those leading zeros do not change the unsigned numeric value.
Convert Hex to Octal Instantly
Use BinaryCon for exact hexadecimal-to-octal conversion, binary regrouping, large input support, verified examples, reference tables, and free number-system tools without registration.