# How many bytes are in one kilobyte?

champion bloodline February 4, 2013

Just curious because I’m deciding which allocation unit size is faster.

1. Prashant Mirjankar
February 25, 2013 at 10:01 am

I believe 1Kb = 1024 bytes = 8192 bits

2. Yashodhan Bhatt
February 13, 2013 at 12:14 pm

You should have goggled that instead!

3. Javaid Hussan
February 12, 2013 at 7:40 pm

1024

February 10, 2013 at 6:27 am

1024

5. Jacob Kraus
February 5, 2013 at 5:28 pm

1024

6. Raazan Malla
February 5, 2013 at 4:25 pm

1024 bytes in one kilobyte

7. Luvrockz Ariph
February 5, 2013 at 1:11 pm
February 5, 2013 at 12:29 pm

@Ayush
It depends how you do the maths pal, break 500Gb into bytes using the 1000 bytes in a Kb method and you will eventually get to 465Gb!
On my 1Tb hard drive which I think you will agree is TWICE the size of a 500Gb hard drive I have 931Gb detected space. Devide that by two (as it double the size of a 500GB) and you will get 465.5Gb.

• Ayush Mittal
February 5, 2013 at 1:03 pm

@You
I Think You Don't Know Maths Pal Don't Mind It Too.
IF I Calculate As You Said Then
500gB=500000mB(Based On Human Thinking 1gB =1000mB)
500000mB=(500000/1024)GB(BAsed On Operating System)
=488.28125GB

Also

1tb=1000gB=1000000MB(Based On Human Thinking 1gB =1000mB)
1000000Mb=(1000000/1024)GB(BAsed On Operating System)
=976.5625GB
Not 931GB

February 5, 2013 at 1:22 pm

Where you are going wrong Ayush is if you start with the number of bytes which is 500000000000 then divide by 1024 to get it into kb you will find you have 488281250 kb.
Devide that by 1024 to convert to Mb and you will find you have 476837MB
Now devide that by 1024 to get it into Gb and you will see 465.6Gb.

An easier way is to click on 'Computer in the start menu and you will see the available space (dending on what veiw you have set).

I understand your line of thinking but you are starting at Mb and not bytes.

• Ayush Mittal
February 8, 2013 at 10:23 am

Ok But Still

• Ayush Mittal
February 8, 2013 at 10:23 am

1024

9. Ayush Mittal
February 5, 2013 at 12:04 pm

Hi There .......
You First See The Difference Between These Two:
Kb & kB.You Might Say They Are Same But In fact The First One(Kb) Is Kilobits While The Other(kB) Is Kilobyte.|
1Kilobyte=8KiloBits.
Also, 1Kilobyte=1024Bytes.
1Kilobyte=(1/(1024))Megabytes OR !Megabyte =1024Kilobyte.

10. Joey Kilian
February 5, 2013 at 11:24 am

Everything what these people said is the answer. 1kb is 1024 bytes and not 1000 as most people think.

11. Imesh Chandrasiri
February 5, 2013 at 3:40 am

1024 bytes.. dude use google for such questions!

12. Ashwin Ramesh
February 5, 2013 at 2:17 am

1024 bytes make 1 Kilobyte and similarly 1024 Kilobytes make 1 Megabyte. You can use this for more conversions of storage units: http://www.convert-me.com/en/convert/computer/

13. Gianna Marie Lanete
February 5, 2013 at 1:02 am

1024 bytes = 1kb

14. Elan Chezhiyan
February 4, 2013 at 9:04 pm

In indian system 1KB = 1024 Bytes and in Western System it is 1KB = 1000 Bytes.
That is the reason for relative diffreence in size of hard disks or pen drives. the notations are given in western system.

15. Ron Lister
February 4, 2013 at 7:41 pm

I was taught 1024bytes is one kilobyte, although the manufacturers seem to have other ideas.

16. Rakesh Pal
February 4, 2013 at 6:58 pm

1KB=1024 bytes

17. Joce Sanchez
February 4, 2013 at 6:04 pm

there are 1024 bytes in a kilobyte

18. Alex Schnapps
February 4, 2013 at 4:57 pm

One letter = one byte. Kilobyte = 8 letters = 8 bytes.

19. Ahmed Musani
February 4, 2013 at 3:38 pm

1 byte= 8 bit. 1 kilobyte(kB)=1024 bytes

20. Lisa Santika Onggrid
February 4, 2013 at 3:08 pm

1B is 8bits, but there's also opening and ending bites so some would say 10.
Likewise, 1KB (Kilobytes) is theoritically 1000 bytes but in machine it'd be 1024. This way hard disk manufacturer can claim their products' storage space to be larger than the actual size. They're using the 1000bytes/kilobytes system while it's actually 1024bytes/kilobytes on disk.

• Rob Hindle
February 4, 2013 at 6:50 pm

Incorrect in several ways. 1 byte is 8 bits. In some situations like error correcting memory there will be additional bits to enable the error correcting function but that's effectively "invisible" for all normal purposes, there are 8 data bits. Similarly in data communications in some situations a byte of data is transmitted with start and stop bits. The data content of one byte remains as 8 bits.

A kilobyte ISN'T 1024 so the hard disk makers can trick us, it's for sound technical reasons. In any case if you were expecting 1000 and got 1024 that sounds like a bonus. In practise there is a discrepancy between the specified capacity of a hard disk and the usable space because some space is used by the disk formatting process and by the disk directory (index). To complain about that is like complaining that when you buy a pad of paper with ruled lines printed on it you are being cheated out of some white space to write on.

• Lisa Santika Onggrid
February 5, 2013 at 11:10 am

Thank you for the explanation. It's clear and concise.

21. prashanth singh rathore
February 4, 2013 at 2:27 pm

1024

• Rakesh Kumar
February 5, 2013 at 2:19 pm

1024

22. babu vhora
February 4, 2013 at 12:47 pm

1024 byte=1 k/b
1024 k/b =1 m/b
1024 m/b =1 g/b
1024 g/b =1 t/b

February 4, 2013 at 12:00 pm

1024 bytes=1 kb cause computer memory uses binary

24. Oron Joffe
February 4, 2013 at 11:38 am

1024 bytes. Because there is confusion between the decimal and binary interpretation of the prefixes (kilo=10,000), a "proper binary" unit called kibibyte (http://en.wikipedia.org/wiki/Kibibyte) has been invented, so theoretically kilobyte=1,000 bytes, and kibibyte=1,024. However, in practice everyone uses kilobyte to mean 1,024.

25. Rob Hindle
February 4, 2013 at 11:02 am

In computer terms a kilobyte is 1024 bytes.
That's because computers work in binary 0s and 1s
so Binary 1 = Decimal 1
Binary 10 = Decimal 2
Binary 100 = Decimal 4
Binary 1000 = Decimal 8
Binary 10000 = Decimal 16

Get the pattern? the position of a 1 indicates its value and in decimal the value doubles for each position.

So combining those we get
Binary 1010 = Decimal 8+2=10
and continuing the pattern 10000000000 is the binary representation of decimal 1024 (did I get the right number of zeros?!)

As you can see it's difficult to deal with all those zeros so programmers work in another number system called hexadecimal (Hex for short). Hex groups the 1s and zeros of a binary number into groups of 4 (keep the leading zeros to show they are groups of 4)
binary 0001 = 1 decimal = 1 Hex
binary 0010 = 2 decimal = 2 Hex
binary 0011 = 3 decimal = 3 Hex

So far so good, but it starts to look odd when we get to decimal 10. in Hex programmers use the letter "A" so we are only using one character position...
binary 1010 = 10 decimal = A Hex
binary 1011 = 11 decimal = B Hex
binary 1100 = 12 decimal = C Hex
binary 1101 = 13 decimal = D Hex
binary 1110 = 14 decimal = E Hex
binary 1111 = 15 decimal = F Hex

That way instead of writing binary 100 0000 0000 to represent decimal 1024 we can write 400. That's confusing. How do you know that 400 is supposed to be a Hex number not Decimal?
There are various ways of showing the difference one is to write the Hex value as #400.

Now you probably know that there are 8 bits in a byte so that's the range 00000000
to 11111111, the hex equivalent is #00 to #FF.

While this is all very important to programmers how does it affect everyone else?
Not much, it just confuses people!

Outside the world of computers Kilo means 1000, Mega means 1,000,000 but in computers Kilo means 1024 (#0400) and Mega means #10 0000 (which in decimal would be 1,048,576). As you can see in Hex we get what I guess we could call "round numbers".

So how does this help with your question? Not a lot! These days computers are so fast and memory/disk storage so cheap even programmers seldom need to worry much but in earlier times it was a lot more important. If you had a program that wrote 513 byte chunks to a hard disk that stored data in half kilobyte blocks (512 bytes) every 513 byte chunk you wrote would have to use 2x512 byte blocks so your expensive disk space would be used up in half the time.

The issue is still there. If you write a file to disk containing a single byte of data it will use at least 512 bytes of disk. That sounds wasteful and if you had a program that wrote loads of small files it would be. It's more common for us to write, say, a wordprocessor file of hundreds or thousands of KB and if sometimes an extra 512 bytes is "wasted" it won't make much difference.

It's a common confusion when people find that the amount of disk space used depends on the software tool they use to measure it (depending on whether it counts the sizes of the files in terms of bytes of data in the file or the number of blocks used by each) - and it gets more confusing still because of space taken up by the directory files on the disk which map out where on the disk each file is stored.

February 4, 2013 at 9:48 am

1024 bytes = 1 kilobyte

27. Jan Fritsch
February 4, 2013 at 9:26 am

File systems and operating systems (except OS X 10.6 and later) usually count in Binary so 1 Kilobyte (or actually called Kibibyte) is 1024 Byte.

As for the allocation unit size it simply depends on the type of files you want to use it for. For example if the cluster size is 4KB it means that any file regardless of it's content uses at least 4KB of space on the hard drive. If you set it to 32KB it would mean that any file will use at least 32KB even if it's some notepad file with a single character in it.

So a larger allocation unit usually makes sense when the files itself are rather large e.g. movies and stuff. For example if most of the files are over 200MB it doesn't really fall into weight whether you waste 3KB from a 4KB allocation unit or 16KB from one 32KB cluster (numbers are just examples).

The benefit of the larger cluster size is that there will be less clusters all together making it faster and less intensive to manage all of them.

On the other hand if you store a lot of small files e.g. office documents using a large cluster size e.g. 32KB will probably result in a lot of wasted space very fast.

In Windows if you right-click and select properties a file or folder you will always get two numbers:
Size …actual file size in Binary Bytes
Size on disk … size used on the disk taking the cluster size into account

• Nicolas De Smyter
February 11, 2013 at 11:05 am

This is a more technical explanation. But as far as I read all the answers, this is the only answer to the question without any mistakes in it

Not a lot of people know that is actually called Kibibytes, Mebibytes etc (http://en.wikipedia.org/wiki/Kibibyte)

1 Kibibyte = 1024 bytes
1 Mebibyte = 1024 Kibibytes
and so on

Manufacturars usally use the term kilobyte (which is also most used in every day use) to note this term. And they also use most of the time 1000 bytes instead of the theoretically correct 1024 bytes.

There is not a single correct answer to this question, there are 2. The theoretically correct answer is 1024 bytes, if you think binary. But if you don't think binary, as most hard disk manufacturers do, it is 1000 bytes.

If you would have asked how much bytes there are in a Kibibyte, there would only be 1 answer: 1024! So if you want to be sure you are talking about the same thing, you should use the term "kibibytes", "mebibytes" etc.

28. muotechguy
February 4, 2013 at 8:49 am

How many grams in a kilogram?

• Rubis Song
February 4, 2013 at 11:33 am

Hahaha...I assume you're just kidding!

February 4, 2013 at 12:49 pm

Is that digital kilograms or binary? :)

February 4, 2013 at 7:56 am

Basically humans like to think of 1000 bytes in a kilabyte and 1000 kilabytes in a megabyte but a computer thinks of it in real terms as 1024 bytes, Megabytes etc. so when you buy a hard drive and the guy selling you it says its a 500 gigabyte drive, he is thinking in human terms when in fact your computer will read it as 465 Gigabytes.
Quite a lot of people think that the "missing" 35Gigabytes is for the recycle bin etc but its not, because its not there to start with.

• Rubis Song
February 4, 2013 at 11:33 am

Very good point Alan. Thank you. In fact I have always believed the "missing" was system dedicated part.
So i believe even manufacturer need to start write in bold 465Gb in their product instead of 500Gb they claim.
Maybe, we human are just having it wrong because of what we use to read.

• Ayush Mittal
February 5, 2013 at 11:59 am

You Should Be Careful While Posting Answers To Others Comment So That You May Not Convey Wrong Info To Him/Her.As Acc. To Your(Alan Wade) Point 500Gb Is Detected By PC As 465Gb Due To 1000mb=1gb normal human thinking;but 1024mb=1gb Computer's Thinking But If This IS So 500Gb Should Be Detected As About 488Gb

• Jozef Fekete
February 11, 2013 at 9:28 am

Alan's answer is ok, because: 500gb = 500,000mb = 500,000,000kb = 500,000,000,000bytes
and
500,000,000,000bytes = 488,281,250kb = 476,837mb = 465gb

• Degenerated Sahoo
February 11, 2013 at 9:50 am

wow!! I was also in confusion...thanx alan ..good point.

30. Irfan P
February 4, 2013 at 7:05 am

One kilobyte equals 1024bytes.

31. Junil Maharjan
February 4, 2013 at 6:52 am

1024 bytes is 1 kilobyte and similarly 1024 kb is 1 mb and so on

32. Avish Kansakar
February 4, 2013 at 5:57 am

when i learned it in school i learned it as 1024 bytes = 1KB

33. susendeep dutta
February 4, 2013 at 5:48 am

Usually,1 KB =1024 bytes,but many manufacturers assume it to be different i.e. 1000 bytes or any other values.

More information on which allocation unit size should be preferable in a given scenario -

http://www.howtogeek.com/136078/what-should-i-set-the-allocation-unit-size-to-when-formatting/