A KB to MB converter divides by 1,000, or by 1,024 the way Windows counts: 2,048 KB is 2.048 MB, or exactly 2 MB. Type any number below and read both, then drop an image to bring it under your limit. Part of the image compressor.
KB
Counting 1,000
2,048,000 bytes · macOS, iPhone and this site
Counting 1,024
2,097,152 bytes · Windows File Explorer
Output format
– / –
Drop images or browse
JPEG · PNG · WEBP · AVIF · HEIC · up to 50 at once · max 30 MB each
HEIC
PNG
JPEG
AVIF
WEBP
Advanced settings1 on
SmallerAutoBetter
Auto tunes each image.
A hard cap for the number your form demands.
KB
A floor for forms that refuse small files.
Max resolution
×
Empty side keeps the ratio. Never enlarges.
Every size target, one guarantee
A page for each number, arriving with the cap already armed. Under it, or a clear error, and never over.
The engine behind the cap, on a real photograph: 9.8 MB in, 97.1 KB out. Your file gets the same treatment with your size limit as the hard ceiling.
How does a KB to MB converter work?
It divides by 1,000. A megabyte is 1,000 kilobytes in the decimal count, the one current Macs and iPhones use, as Apple’s page on storage capacity sets out, so 2,048 KB is 2.048 MB. Windows File Explorer divides by 1,024 instead, so the same file reads as 2 MB there. The converter above prints both counts with the bytes behind each, and its swap button turns it round to MB to KB.
How many KB in an MB?
1,000 in the decimal count and 1,024 in the binary one. One megabyte is then 1,000,000 bytes or 1,048,576, about 5% apart, and the gap grows with each step up: at a gigabyte it is over 7%. The international standard names the binary units kibibytes and mebibytes, KiB and MiB, so that KB and MB can keep their decimal meaning. Windows counts in binary but still writes KB and MB.
Why does one file show two sizes?
Because the two computers count differently. Our camera photo is 9,804,300 bytes. A Mac divides by 1,000 twice and shows 9.8 MB; Windows divides by 1,024 twice and shows about 9.35 MB. Neither is wrong, and the file has not changed between them. When a limit matters, the bytes are the truth, and the converter above prints them.
Which count does an upload form use?
The form checks bytes, and prints them either way. Immigration New Zealand writes its visa photo window as 512 KB to 3.14 MB, which matches 500 KB and 3 MB counted by 1,024. The safe move is to stay under the smaller reading of the limit. This site counts 1,000 in its size field and in every size it prints, so a file capped at 3 MB here is 3,000,000 bytes, under the ceiling by either count, and the result prints those bytes in full: the compress image to 3 MB page arms exactly that.
Can I increase image size in KB?
Yes, up to what the picture holds. Type the number into Min file size in Advanced settings, and the engine raises quality until the file reaches it; it never pads a file with empty bytes. Our reference photo cropped to a 200 px square weighs 8.1 KB at Auto and came back at 10.4 KB under a 10 KB floor. At 150 px it reached the floor too, at 10 KB. A picture too small for the floor at the highest quality is refused in words instead of met with filler. Then add pixels with the Custom size in the image resizer, which adds bytes but no detail. A minimum is rarely the problem, though: our 9.8 MB camera photo came back at 1.9 MB under a 2 MB cap, far above any floor we have met.
The number is in MB and must become KB
Use the swap button, or the MB to KB page when an image has to come down that far.
A form rejects a file that looks small enough
Check the bytes against the smaller reading of the limit, then cap the file below it.
You need a bigger file, not a smaller one
Set Min file size and quality rises to reach it. Past what the pixels hold, add pixels.
Questions, answered
The panel is already open above. One drop settles most of these.
Q:What is 500 KB in MB?
0.5 MB counting 1,000, the way a Mac and this site count, and about 0.49 MB counting 1,024, the way Windows does. Either way a 500 KB file passes a 1 MB limit with room. Type any other number into the converter at the top of the page and both counts print at once, with the bytes behind each.
Q:Is 1 MB 1,000 KB or 1,024 KB?
Both are in use. The decimal count, the one the international standard and current Macs and iPhones follow, puts 1,000 KB in an MB. The binary count, which Windows File Explorer shows, puts 1,024 in it. The standard calls the binary units kibibytes and mebibytes, KiB and MiB, but Windows writes KB and MB for them anyway.
Q:How many MB is 1,024 KB?
Exactly 1 MB counting 1,024, and 1.024 MB counting 1,000. That one number is where the two counts part: a file Windows calls 1 MB is 1,048,576 bytes, which is 1.05 MB counting 1,000. The swap button on the converter turns it round to MB to KB.
Q:How many KB is 5 MB?
5,000 KB counting 1,000, or 5,120 KB counting 1,024. In bytes, 5,000,000 or 5,242,880. A form that says 5 MB is safe with the smaller figure. The compress image to 5 MB page arms a cap of 5,000,000 bytes, so what it hands back passes a checker that uses either count.
Q:What are KiB and MiB?
The names the international standard gives the binary units, so that KB and MB can keep their decimal meaning. A kibibyte, KiB, is 1,024 bytes and a mebibyte, MiB, is 1,048,576 bytes. Some Linux tools print them. Windows counts the same way but labels the result KB and MB, which is where most of the confusion starts.
Q:How do I convert MB to KB?
Multiply by 1,000, or by 1,024 for the Windows count: 2 MB is 2,000 KB or 2,048 KB. The swap button on the converter does it in place. When the job is an image that has to come down from megabytes to a kilobyte limit, the compress image from MB to KB page does the compressing too.
Q:Does the converter upload anything?
No. The KB to MB converter is arithmetic that runs in your browser, and nothing leaves the page for it. The compressor under it is separate: drop an image there and it comes back at or under the size you type, up to 50 at a time, EXIF stripped, with the files wiped automatically.
Q:How do I get an image under a limit in KB or MB?
Type the limit into Max file size in the panel under the converter, pick KB or MB, and drop the image. The engine searches for the most quality that fits and hands back a file at or under the number. Our 9.8 MB camera photo came back at 1.9 MB under a 2 MB cap, every pixel kept.
