256
256 is 2⁸ — the number of distinct values a single byte can hold.
Where 256 fits
Why 256 is special
256 is why so many limits in computing are 255: a byte holds 2⁸ = 256 values, and counting from zero makes the largest 255. It is the size of the extended character sets, the range of each colour channel in 24-bit images, and the reason an eight-bit game could show exactly 256 of anything before something had to give.
Same number, different meanings
How 256 is understood across different contexts — never implying one meaning because of another.
- Mathematics
256 is why so many limits in computing are 255: a byte holds 2⁸ = 256 values, and counting from zero makes the largest 255. It is the size of the extended character sets, the range of each colour channel in 24-bit images, and the reason an eight-bit game could show exactly 256 of anything before something had to give.
- Everyday life
A single byte holds 256 distinct values, so limits expressed as 255 are almost always one byte with zero counted. It is why colour channels stop at 255 and why older systems refused a 256th item.
- Technology & computing
A byte holds 2⁸ = 256 distinct values, and counting from zero makes the largest one 255. That is why so many maximums are 255 rather than 256: colour channel intensities, the largest value in an unsigned 8-bit field, and the classic arcade 'kill screen' where a counter wraps past its byte.
- Geography
+256 reaches Uganda, which has among the world's youngest median ages. Its demographic profile shapes everything from schooling to mobile adoption more than most policy does.
256 is part of
Factors & digit properties
- Divisors (9)
- 1, 2, 4, 8, 16, 32, 64, 128, 256
- Prime factorisation
- 2^8
- Digit sum
- 13
- Digital root
- 4
Representations
- Decimal
- 256
- Binary
- 100000000
- Octal
- 400
- Hexadecimal
- 100
- Roman numeral
- CCLVI
- Scientific notation
- 2.560 × 10^2
Other mathematical patterns
- Deficient number
- Powerful number
Related numbers & connections
Consecutive powers of two, and consecutive units of storage history: 256 values in a byte, 512 bytes in the disk sector that file systems assumed for decades. Doubling is the only step the binary world takes.
View 512 →256 is 2⁸, the number of values a byte holds, and the reason so many computing limits land on 255.
256 values per channel across three channels gives 16,777,216 colours. The large number is entirely a consequence of the small one being cubed.
View 16777216 →Mathematically related
Shares a distinctive class
- is associated withPowers of two
why?
Strength 0.50, confidence "high".
Other connections
- is associated with16777216
why?
Strength 0.50, confidence "high".
Everyday life
A single byte holds 256 distinct values, so limits expressed as 255 are almost always one byte with zero counted. It is why colour channels stop at 255 and why older systems refused a 256th item.
DocumentedEveryday lifeGeography: GlobalPeriod: 1960s–
Technology & computing
A byte holds 2⁸ = 256 distinct values, and counting from zero makes the largest one 255. That is why so many maximums are 255 rather than 256: colour channel intensities, the largest value in an unsigned 8-bit field, and the classic arcade 'kill screen' where a counter wraps past its byte.
DocumentedTechnology & computing
Geography
+256 reaches Uganda, which has among the world's youngest median ages. Its demographic profile shapes everything from schooling to mobile adoption more than most policy does.
DocumentedGeographyGeography: Uganda
Mathematics
256 = 2⁸ = 4⁴ = 16², which is why it recurs at several different levels of the same systems: sixteen hexadecimal values per digit, two hex digits per byte, 256 values per byte. The nesting is the reason hexadecimal and binary interconvert so cleanly that programmers read one as the other.
DocumentedMathematics
Common questions
Is 256 a prime number?
No, 256 is not prime.
What are the factors of 256?
The factors of 256 are 1, 2, 4, 8, 16, 32, 64, 128, 256.
What is 256 in Roman numerals?
256 in Roman numerals is CCLVI.
About this page's data
Mathematical facts:computed directly from the number's value — nothing to source or verify externally.
Contextual records: 4 reviewer-confirmed records, sourced and reviewed before publication.
Last reviewed: 3 August 2026