Welcome to our Hexadecimal to Octal Converter, a free online tool that moves values from base 16 into base 8. These two systems come from the same family, since sixteen is two to the fourth power while eight is two to the third, so the trip between them is a neat and predictable one.

Hexadecimal gets by with the digits 0 to 9 plus the letters A to F, sixteen symbols in all. Octal is slimmer, using only 0 through 7. Each base has carved out its own corner of the computing world, and this page is where the two meet.

Students run into these conversions while learning how number systems relate, and engineers run into them when tools and older systems ask for octal. Whatever your reason, the converter answers in a moment. As a quick taste, the hex value FF becomes the octal value 377.

Hexadecimal Number System

The hexadecimal number system, also called base 16, is the compact way to write machine data that humans find easiest to scan. It uses sixteen symbols: the digits 0 to 9 and the letters A to F, where A counts for 10, B for 11, and so on up to F for 15.

Look at the value "5B". The digit 5 sits in the sixteens column, so it contributes 5 × 16 = 80. The digit B stands for 11 and sits in the ones column, adding 11. Together they come to 91 in decimal.

Hexadecimal also translates cleanly to bits. Each hex digit is a fixed bundle of four binary digits, so 5 becomes 0101 and B becomes 1011. That makes 5B equal to the eight-bit string 01011011.

Therefore, the hexadecimal number (5B)₁₆ is the same number as (91)₁₀ and (133)₈.

Octal Number System

The octal number system, or base 8, works with only eight digits, from 0 up to 7. Each column is a power of eight, climbing as 1, 8, 64, 512, and so forth. Because three bits can form exactly eight combinations, a single octal digit always represents three bits.

Read the octal value "133" from right to left. The rightmost 3 is worth 3, the middle 3 is worth 3 × 8 = 24, and the leftmost 1 is worth 1 × 64 = 64. Adding them gives 91, the same decimal value we reached for 5B.

Therefore, the octal number (133)₈ is the same number as (91)₁₀ and (5B)₁₆.

Here is the relationship that drives this page. A hexadecimal digit covers four bits while an octal digit covers three. Because both bases are powers of two, any hex value can become octal by expanding it to binary and then grouping those bits into threes.

Type a hexadecimal value and press "Convert to Octal" to get its base-8 form right away. Prefer the full picture? Press "Convert to All" and the tool also fills in the decimal and binary equivalents, which makes it easy to compare one number across several bases.

The octal result can be copied to your clipboard, the fields can be cleared with a click, and the whole set of conversions can be saved as a text file. There is nothing to install, no sign-up, and no cost.

At a Glance:

For an integer hexadecimal number , expand each hex digit into its four-bit nibble and join the nibbles into one long binary string. Then split that string into groups of three bits, starting from the right, and translate each group into the matching octal digit.

For a fractional value , separate the number at the decimal point first. Regroup the integer part from the right and the fractional part from the left, adding zeros at the outer ends so that every group is complete. Combine the results around the point.

In Detail:

If the description above feels abstract, the steps below with the example A3F.8 should make it concrete.

Step 1: Split the value into its integer part A3F and its fractional part .8.

Step 2: Expand every hex digit into four bits. A becomes 1010, 3 becomes 0011, and F becomes 1111, giving the string 101000111111.

Step 3: Regroup the integer bits in threes from the right. The string splits as 101, 000, 111, 111, which map to the octal digits 5, 0, 7, 7. So the integer part is 5077.

Step 4: Handle the fraction. Expand .8 into its nibble 1000, then group from the left in threes, padding zeros at the far end: 100 and 000. Those give the octal digits 4 and 0, so the fraction is .40, which we write as .4.

Step 5: Join the parts to get 5077.4.

Therefore, the hexadecimal number (A3F.8)₁₆ equals (5077.4)₈.

Whenever you need to know what a three-bit group means, the table below is your quick reference.

Bits	Octal Digit
000	0
001	1
010	2
011	3
100	4
101	5
110	6
111	7

If the regrouping ever feels fiddly, the positional route still works. Convert each hex digit with its power of 16 to reach the decimal value, then express that decimal value in base 8 by dividing by 8 repeatedly. The bit method is simply the shortcut that makes the math visible.

Example 1: Hexadecimal to Octal Conversion: ABC.
To convert the hexadecimal number ABC into octal, follow these steps:

Step 1: Expand each hex digit into its nibble: A → 1010, B → 1011, and C → 1100.
Step 2: Join the nibbles to get the binary string 101010111100.
Step 3: Regroup from the right in threes: 101 010 111 100.
Step 4: Read off the octal digits 5, 2, 7, and 4. Thus, the octal equivalent of (ABC)₁₆ is (5274)₈.

Example 2: Hexadecimal to Octal Conversion: 3F.C.
To convert the hexadecimal number 3F.C into octal, follow these steps:

Step 1: Separate the value into the integer part 3F and the fractional part .C.
Integer Part (3F):
Step 2: Expand the nibbles: 3 → 0011 and F → 1111, giving 00111111.
Step 3: Regroup from the right in threes: 111 111.
Step 4: Translate the groups to get 77.
Fractional Part (C):
Step 5: Expand .C, which stands for 12, into its nibble 1100.
Step 6: Regroup from the left in threes, padding at the far end: 110 000.
Step 7: Translate the groups to get .6. Combining the two halves, the octal equivalent of (3F.C)₁₆ is (77.6)₈.

Example 3: Hexadecimal to Octal Conversion: FFA.
To convert the hexadecimal number FFA into octal, follow these steps:

Step 1: Expand each hex digit into its nibble: F → 1111, F → 1111, and A → 1010.
Step 2: Join the nibbles to get 111111111010.
Step 3: Regroup from the right in threes: 111 111 111 010.
Step 4: Read off the octal digits 7, 7, 7, and 2. Therefore, the octal equivalent of (FFA)₁₆ is (7772)₈.

This converter is easy to recommend, and the reasons go beyond the obvious. Here is what you get:

Saves Your Time:

Manual conversion, especially for long values, means juggling nibbles and groups of three. This tool does all of that in an instant, leaving you with the answer and none of the fuss.

No Account Needed:

You will not be asked to register, log in, or leave an email address. Open the page, convert, and move on with your day.

Instant Feedback:

The conversion happens right in your browser, so the octal result appears as soon as you click. No uploads, no waiting.

Dependable Results:

The tool applies the same positional math every time, so the output is something you can trust when checking your own work or your code.

Works Everywhere:

Any modern browser on a phone, tablet, or computer will run it. Windows, macOS, Linux, iOS, and Android are all covered.

Free Forever:

Every feature here is free, including Convert to All and the download option. There are no trials, no limits, and no surprise charges.

Comfortable With Long Inputs:

Whether it is a two-digit hex value or a long chain of digits, the tool converts without breaking a sweat. Results are exact for values up to about 14 hex digits (roughly 9 quadrillion); for extremely long values, JavaScript number precision may round the final digits.

FAQ 1: Is this tool really free?
Answer: Yes, completely. There is no registration, no subscription, and nothing to download or install.

FAQ 2: Why do hex digits cover four bits while octal digits cover three?
Answer: Because 16 equals 2 raised to the fourth power and 8 equals 2 raised to the third. Four bits can express sixteen combinations, while three bits can express exactly eight.

FAQ 3: Can I type lowercase letters?
Answer: Yes. Inputs such as ff and 1a are treated exactly like their uppercase forms.

FAQ 4: Does it handle fractional values?
Answer: Yes. Fractional parts are converted with the same logic, so 2F.4 comes back as 57.2.

FAQ 5: Where does octal actually show up in real life?
Answer: Most famously in Unix and Linux file permissions, where three-digit octal codes like 755 describe who can read, write, and run files. Older systems and legacy documentation also use it.

FAQ 6: Why route the conversion through binary at all?
Answer: Because both hexadecimal and octal are powers of two, binary is the natural common ground between them. Expanding to bits and regrouping is the quickest mental path, and the tool applies exactly that method for you.