Convert kilobytes to megabytes. Divide by 1000, with typical file sizes and the kB, KB and KiB distinction explained.

The formula

MB = kB ÷ 1000

In SI units a megabyte is a thousand kilobytes. If the source means binary units, the divisor is 1024 — a 2.4% difference, which at this scale is the smallest it ever gets.

kB, KB and KiB

Three spellings, two quantities, and this is the level at which the distinction was born:

Written	Means	Bytes
`kB`	kilobyte, SI	1000
`KB`	kilobyte, used loosely for both	1000 or 1024
`KiB`	kibibyte, unambiguous	1024

SI reserves the lower-case k for the kilo prefix — an upper-case K is kelvin — so kB is the strictly correct decimal form. In practice almost everything writes KB and means whichever its author had in mind.

Quick reference

kB	MB
1 kB	0.001 MB
100 kB	0.1 MB
500 kB	0.5 MB
1000 kB	1 MB
1024 kB	1.024 MB
5000 kB	5 MB

Typical file sizes

Kilobytes are the natural unit for things made of text, and the scale is a useful reminder of how much prose fits into how little space:

	Kilobytes
Plain text, 1000 words	6 kB
This page’s HTML	20–40 kB
Favicon	5–15 kB
Web font, one weight	20–40 kB
Optimised JPEG, web size	60–200 kB
PNG screenshot	200–800 kB
PDF, text-only, 10 pages	100–300 kB
MP3, 4 minutes at 128 kbps	3800 kB

The whole text of a long novel is around 1 MB. A single phone photograph is three to five times that.

Web performance

Page weight is the one place kilobytes are still the working unit, because the difference between 200 kB and 2 MB is the difference between a page that loads on a train and one that does not:

Page weight	On 4G (20 Mbps)	On 3G (1.5 Mbps)
200 kB	0.08 s	1.1 s
500 kB	0.2 s	2.7 s
1000 kB	0.4 s	5.3 s
3000 kB	1.2 s	16 s

Those figures are transfer time alone, and ignore latency, TLS setup and the time spent parsing what arrives — all of which usually dominate on a small page.

Estimating in your head

Move the decimal point three places. 2500 kB is 2.5 MB.

KB to MB