By Tim King · Updated 1 October 2026

Bytes to KB and KB to Bytes Converter

Decimal KB and Binary KiB Explained, Bytes Divided by 1,000 or 1,024

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bytes to kilobytes formula

KB = bytes ÷ 1,000

1 byte = 0.001 kilobytes, so multiply bytes by 0.001. Going the other way, 1 kilobyte = 1,000 bytes.

bytes to kilobytes table

bytes (B)	kilobytes (KB)
1	0.001
8	0.008
64	0.064
100	0.1
128	0.128
256	0.256
500	0.5
512	0.512
1,000	1
1,024	1.024
1,500	1.5
2,048	2.048
4,096	4.096
5,000	5
8,192	8.192
10,000	10
16,384	16.384
32,768	32.768
65,536	65.536
100,000	100
1,000,000	1,000

How many kilobytes in bytes?

100 B = 0.1 KB. There are 0.1 kilobytes in 100 bytes.

512 B = 0.512 KB. There are 0.512 kilobytes in 512 bytes.

1,000 B = 1 KB. There are 1 kilobytes in 1,000 bytes.

1,024 B = 1.024 KB. There are 1.024 kilobytes in 1,024 bytes.

10,000 B = 10 KB. There are 10 kilobytes in 10,000 bytes.

kilobytes to bytes formula

bytes = KB × 1,000

1 kilobyte = 1,000 bytes, so multiply kilobytes by 1,000, or divide by 0.001.

kilobytes to bytes table

kilobytes (KB)	bytes (B)
0.5	500
1	1,000
1.024	1,024
2	2,000
4	4,000
5	5,000
8	8,000
10	10,000
14	14,000
16	16,000
20	20,000
32	32,000
50	50,000
64	64,000
100	100,000
128	128,000
250	250,000
500	500,000
1,000	1,000,000

How many bytes in kilobytes?

1 KB = 1,000 B. There are 1,000 bytes in 1 kilobytes.

4 KB = 4,000 B. There are 4,000 bytes in 4 kilobytes.

10 KB = 10,000 B. There are 10,000 bytes in 10 kilobytes.

64 KB = 64,000 B. There are 64,000 bytes in 64 kilobytes.

100 KB = 100,000 B. There are 100,000 bytes in 100 kilobytes.

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How the Bytes To KB works

This bytes to kb converter divides by 1,000 as you type, using the decimal kilobyte defined by the SI and used by macOS, iOS and storage makers. The explainer and table also give the binary kibibyte of 1,024 bytes that Windows reports and labels KB. Press the swap button to turn kilobytes into bytes.

A byte is eight bits, enough to hold one character of plain English text. File sizes, upload limits and memory are all counted in bytes, but almost nobody reads them that way: 48,213 bytes is easier to grasp as 48 KB. The catch is that "KB" means two different numbers depending on who wrote it.

Bytes to kb: 1,000 or 1,024?

Kilobyte (kB or KB), decimal: exactly 1,000 bytes, as defined by the SI prefix kilo. macOS since 10.6, iOS, Android, Linux desktop tools and drive makers all count this way.
Kibibyte (KiB), binary: exactly 1,024 bytes, or 2¹⁰. The IEC named it in 1998 to end the ambiguity. Windows Explorer still counts in KiB but labels the result KB.
Memory: RAM sizes are powers of two, so a "4 KB" memory page is 4,096 bytes.

The formula

KB = bytes ÷ 1,000, and bytes = KB × 1,000. For binary units, KiB = bytes ÷ 1,024. The difference between the two is 2.4% at this scale and grows with each prefix.

Worked examples

The first example is an email attachment limit check. A file of 1,536,000 bytes is 1,536,000 ÷ 1,000 = 1,536 KB, or 1,500 KiB in Windows Explorer.

The second example goes the other way. A web form that caps avatars at 200 KB accepts up to 200 × 1,000 = 200,000 bytes, unless the developer meant 204,800 bytes in binary.

A third example: a plain text file of 4,096 bytes shows as 4.1 KB on a Mac and 4 KB in Windows.

How many bytes in a kilobyte, and common sizes

There are 1,000 bytes in a decimal kilobyte and 1,024 bytes in a binary kibibyte. The table converts common byte counts, many of them powers of two, into both.

Common byte counts in decimal kilobytes and binary kibibytes

Bytes	KB (1,000)	KiB (1,024)
1	0.001	0.00098
8	0.008	0.0078
100	0.1	0.098
256	0.256	0.25
512	0.512	0.5
1,000	1	0.977
1,024	1.024	1
1,500	1.5	1.465
2,048	2.048	2
4,096	4.096	4
5,000	5	4.883
8,192	8.192	8
10,000	10	9.766
16,384	16.384	16
32,768	32.768	32
50,000	50	48.83
65,536	65.536	64
100,000	100	97.66
131,072	131.072	128
250,000	250	244.1
500,000	500	488.3
1,000,000	1,000	976.6

How to read the result

B equals gives the size in decimal kilobytes, for example 4,096 B equals 4.096 KB.
Conversion shows the factor, 1 B = 0.001 KB. After a swap it reads 1 KB = 1,000 B.
Inverse gives the factor for the opposite direction.

If you need the Windows figure, divide the bytes by 1,024 instead, or multiply this result by 0.9766.

Tips and pitfalls

Lowercase b is bits. 1 kb is a kilobit, 125 bytes. Network speeds use bits; file sizes use bytes.
Check which convention a limit uses. Upload limits in web code are often written as 1024 × n, so a "100 KB" cap may allow 102,400 bytes.
Small files take more disk space. A disk stores files in clusters, often 4,096 bytes, so a 10-byte file still uses 4 KiB on disk.
Bigger units next. For megabytes, use the KB to MB converter, and for the binary units in depth, GB to GiB.

FAQ

How many bytes are in a kilobyte?

A decimal kilobyte is exactly 1,000 bytes, which is the SI definition used by macOS, phones and drive makers. Windows and older textbooks use 1,024 bytes, which is properly called a kibibyte and written KiB.

Is 1 KB 1,000 or 1,024 bytes?

Both are in use. The international standard since 1998 says 1 KB is 1,000 bytes and 1 KiB is 1,024 bytes. Windows still shows 1,024-byte units labelled KB, which is why file sizes differ between Windows and a Mac.

How many KB is 1,024 bytes?

1,024 bytes is 1.024 decimal kilobytes, or exactly 1 binary kibibyte. It is the size Windows shows as 1 KB, and it is the classic power-of-two figure that computer memory is built around.

What is the difference between KB and kb?

KB, or kB, is a kilobyte, 1,000 bytes. Lowercase kb is a kilobit, 1,000 bits, which is only 125 bytes. Network and modem speeds use kilobits, while file and memory sizes use kilobytes.

How many characters fit in a kilobyte?

About 1,000 characters of plain English text, since each basic Latin letter takes one byte in UTF-8. Accented letters take two bytes and most emoji take four, so text in other scripts fits fewer characters per kilobyte.