Binary to Hex Converter

To convert binary to hex, split the bits into groups of four starting from the right, pad the leftmost group with zeros, and replace each group with one hex digit. For example, 101101101 groups as 0001 0110 1101, which reads 1, 6 and D, so the result is 16D.

BINbinary

HEXhex

Hex to binary

Method: Group bits by four from the right

Regroup in 4s from the point outward (pad: 3 zeros on the left)
Group	Hex digit
0001	1
0110	6
1101	D

Result: 16D.

How to convert binary to hex by hand

Long runs of ones and zeros are hard to read and easy to miscopy. Cutting them into fours turns them into hex, which is the shorthand people actually use for bit patterns; every group of four maps to exactly one digit.

Start at the rightmost bit, the ones place.
Mark off groups of four bits moving left.
Pad the last, leftmost group with zeros until it also has four bits.
Replace each group with its hex digit, 0000 = 0 through 1111 = F.
Write the digits in the same left-to-right order.

Paste binary with or without spaces, underscores or a 0b prefix; the converter ignores the formatting and regroups the bits itself. A trailing b, as in some assembly syntaxes, is read as a binary marker too.

Worked example: 1 0110 1101

Nine bits: two full groups and a single leftover bit

101101101₂ = 16D₁₆

Regroup in 4s from the point outward (pad: 3 zeros on the left)
Group	Hex digit
0001	1
0110	6
1101	D

Result: 16D.

The grouping mistake that gives a wrong answer

Grouping from the left feels natural because that is how we read, and when the bit count is a multiple of four it even works. With nine bits it does not. Starting at the left gives 1011 0110 1; padding that stray bit on the right turns it into 1000, and you get B68, which is 2920 instead of 365.

The ones place is always the rightmost bit, so that is where the first group must end. Pad on the left, where extra zeros cost nothing.

The same nine bits grouped two ways
Grouping	Groups	Hex	Decimal
From the right	0001 0110 1101	16D	365
From the left (wrong)	1011 0110 1000	B68	2920

Binary fractions

After the point the direction reverses. Bits to the right of the point are grouped starting at the point and moving right, and the last group is padded with zeros on its right. In 101.1 the whole part pads to 0101 and the fraction to 1000, giving 5.8.

Both readings agree in decimal: one half is 0.5, and 8 sixteenths is also 0.5, so the value is 5.5 either way. A fraction with a finite number of bits always ends in hex, because every group of four bits is one exact hex digit.

101.1₂ = 5.8₁₆ = 5.5₁₀

Regroup in 4s from the point outward (pad: 1 zero on the left, 3 zeros on the right)
Group	Hex digit
0101	5
.	.
1000	8

Result: 5.8.

Questions people ask

Why do you group binary digits from the right?

The groups have to line up with the ones place. Grouping 101101101 from the right gives 1 0110 1101 = 16D. Grouping from the left gives 1011 0110 1, and the last single bit no longer sits in the ones place, so the answer comes out wrong.

What if the number of bits is not a multiple of four?

Add zeros on the left until it is. Leading zeros do not change the value, so 101 becomes 0101, which is the hex digit 5.

What is 11111111 in hex?

FF. The two groups 1111 and 1111 are both F. It is 255 in decimal, the largest value that fits in one byte.

How do you convert a binary fraction to hex?

Group the bits after the point in fours from the left and pad with zeros on the right. 101.1 becomes 0101.1000, which is 5.8 in hex, or 5.5 in decimal.

Last updated October 5, 2026