A megabyte (MB) is bigger than a kilobyte (KB). One megabyte equals 1,000 kilobytes in the decimal system used by storage makers and the international SI standard. In the binary system that Windows and some other software use, it equals 1,024 kilobytes. Either way, an MB is about a thousand times larger than a KB.
Here’s an easy way to remember it: the “kilo” in kilobyte means thousand, as in a kilometer, and “mega” means million. So a kilobyte is about a thousand bytes and a megabyte is about a million.
File Sizes From Smallest to Largest
The common data storage units, from smallest to largest, are the bit, byte, kilobyte, megabyte, gigabyte and terabyte. Each step up the list is about 1,000 times bigger than the one before it.
- Bit (b). A bit is the smallest unit of digital data, a single 0 or 1.
- Byte (B). A byte is 8 bits, which is about enough to store one text character like the letter “A.”
- Kilobyte (KB). A kilobyte is 1,000 bytes, roughly a couple of paragraphs of plain text.
- Megabyte (MB). A megabyte is 1,000 KB. A phone photo or a few minutes of MP3 music is a few megabytes.
- Gigabyte (GB). A gigabyte is 1,000 MB. Phone storage, app downloads and data plans are measured in gigabytes.
- Terabyte (TB). A terabyte is 1,000 GB, a common size for laptop drives, external hard drives and cloud backup plans.
Bigger units come after the terabyte: the petabyte (PB), exabyte (EB), zettabyte (ZB), yottabyte (YB), ronnabyte (RB) and quettabyte (QB).
How Many KB Are in an MB? Decimal vs. Binary
One megabyte holds 1,000 kilobytes in decimal units and 1,024 kilobytes in binary units. Both numbers are in common use, which is why some sources give one answer and some give the other.
The difference comes from how computers count. People count in tens, so “kilo” means 1,000. Computers work in powers of two, and 2 to the 10th power is 1,024. That’s close enough to 1,000 that early programmers borrowed the “kilo” label for it.
To end the confusion, the International Electrotechnical Commission created separate binary names. A kibibyte (KiB) is exactly 1,024 bytes, and a mebibyte (MiB) is exactly 1,024 KiB, or 1,048,576 bytes. Officially, KB and MB are decimal units. In practice, many operating systems, including Windows, still do the math in binary and show the result as “KB” and “MB.”
| Unit | Decimal size (bytes) | Binary size (bytes) | Binary name |
|---|---|---|---|
| 1 kilobyte (KB) | 1,000 | 1,024 | Kibibyte (KiB) |
| 1 megabyte (MB) | 1,000,000 | 1,048,576 | Mebibyte (MiB) |
| 1 gigabyte (GB) | 1,000,000,000 | 1,073,741,824 | Gibibyte (GiB) |
| 1 terabyte (TB) | 1,000,000,000,000 | 1,099,511,627,776 | Tebibyte (TiB) |
How to Convert KB to MB (and Back)
To convert KB to MB, divide the number of kilobytes by 1,000. To go from MB to KB, multiply by 1,000. If the number comes from Windows or another program that uses binary units, use 1,024 instead.
| Kilobytes (KB) | Megabytes (MB), decimal ÷ 1,000 | Megabytes (MB), binary ÷ 1,024 |
|---|---|---|
| 100 KB | 0.1 MB | 0.098 MB |
| 500 KB | 0.5 MB | 0.49 MB |
| 1,000 KB | 1 MB | 0.98 MB |
| 2,500 KB | 2.5 MB | 2.44 MB |
| 10,000 KB | 10 MB | 9.77 MB |
Worked example: Suppose a website says your photo upload must be under 2 MB, and your file shows as 1,950 KB. Divide 1,950 by 1,000 and you get 1.95 MB. Divide by 1,024 and you get 1.90 MB. Either way the photo is under the limit. When a file sits right at the edge of a limit, the two methods can disagree, so leave yourself a little room.
What Is Bigger, KB or MB, on Your Phone or Computer?
An MB is bigger than a KB on every phone and computer. The only thing that changes from device to device is whether it counts 1,000 or 1,024 KB to the megabyte. You can check any file’s size yourself:
- Windows. Right-click the file and choose Properties. Windows uses binary math but labels the units KB, MB and GB.
- Mac. Select the file and choose File > Get Info. Modern macOS uses decimal units, so 1 MB means 1,000 KB.
- iPhone and Android. Open the storage section in Settings to see how much space apps and media use. To see one file’s size, open the file’s details in the Files app or your phone’s file manager.
The mixed methods explain a common surprise. A drive sold as 1 TB holds 1 trillion bytes, but Windows divides by 1,024 three times and shows about 931 GB. No space is missing. The same amount is just being counted in two different ways.
MB vs. Mb: Bytes and Bits Are Not the Same
A capital “B” means bytes, and a lowercase “b” means bits. One byte equals 8 bits. That makes a megabyte (MB) eight times bigger than a megabit (Mb).
This matters most with internet speeds, which are sold in megabits per second (Mbps). Download progress bars, on the other hand, usually show megabytes per second (MB/s). A 100 Mbps connection tops out at about 12.5 MB per second, because 100 divided by 8 is 12.5. If your downloads seem eight times slower than the speed on your bill, this unit difference is the reason.
The capitalization of “k” is a different story. The official SI symbol for kilo is a lowercase “k,” so you’ll see both “kB” and “KB.” Both mean kilobyte.
Common KB and MB Mix-Ups
- Reading the bigger number as the bigger file. 900 KB is smaller than 1 MB. Always check the unit before comparing the numbers.
- Mixing up bits and bytes. Mbps (megabits) measures connection speed. MB (megabytes) measures file size. They differ by a factor of 8.
- Thinking new storage is defective. A smaller-than-advertised capacity usually comes from the decimal-versus-binary difference plus space taken by the operating system.
- Assuming everyone uses 1,024. Drive makers and macOS use 1,000. Windows uses 1,024. Check which one your source uses when you need an exact figure.
FAQ
– Is 500 KB a large file?
No, 500 KB is a small file, about half a megabyte. That’s typical of a compressed photo, a short PDF or a document with a few images. It’s well under the attachment limits of major email services and fine for most upload forms.
– What is the largest memory unit?
The quettabyte (QB) is the largest official named unit. It equals 10 to the 30th power bytes. The ronnabyte and quettabyte became official in 2022, when the SI prefixes “ronna” and “quetta” were adopted. Before that, the yottabyte was the largest.
– Which is bigger, KB, MB or GB?
A gigabyte (GB) is the biggest of the three, followed by the megabyte (MB) and then the kilobyte (KB). One GB equals 1,000 MB, or 1,000,000 KB in decimal units. In binary units, 1 GB equals 1,024 MB.
– What do KB, MB, GB, TB, PB, EB, ZB and YB stand for?
These abbreviations stand for kilobyte, megabyte, gigabyte, terabyte, petabyte, exabyte, zettabyte and yottabyte. Each unit is about 1,000 times larger than the one before it. Their binary versions are named KiB, MiB, GiB, TiB and so on.
– What is the difference between MB and GB?
A gigabyte (GB) is 1,000 times bigger than a megabyte (MB), or 1,024 times bigger in binary units. Single files like photos and songs are usually measured in megabytes. Phone storage, data plans and large downloads like games are usually measured in gigabytes.