KB to MB Converter (Kilobytes to Megabytes)
Enter a value in kilobytes to convert it to megabytes. Choose between the binary convention used by operating systems (1 MB = 1,024 KB) and the SI decimal convention used by storage manufacturers (1 MB = 1,000 KB). You can also run the conversion in reverse: enter megabytes to get kilobytes. The result updates as you type.
How to convert kilobytes to megabytes
The conversion depends on which standard you are using. Under the binary convention used by operating systems, there are exactly 1,024 kilobytes in one megabyte: MB = KB / 1,024. Under the SI decimal convention used by most storage device manufacturers, there are 1,000 kilobytes in one megabyte: MB = KB / 1,000. For a file your OS reports as 2,048 KB, the binary conversion gives exactly 2 MB. The same file under the SI standard would be 2.048 MB.
Why does my hard drive show less space than advertised?
Storage manufacturers label capacity using SI prefixes: 1 MB = 1,000 KB, 1 GB = 1,000 MB, 1 TB = 1,000 GB. Your operating system measures the same space using binary prefixes: 1 MB = 1,024 KB, 1 GB = 1,024 MB, 1 TB = 1,024 GB. A drive sold as 1 TB contains 1,000,000,000,000 bytes. Divide by 1,024^4 (binary GB) and you get about 909.5 GiB, which Windows displays as roughly 909 GB. The bytes are all there - it is just a labelling difference between two valid conventions. Using our converter and switching between SI and binary lets you see exactly where the gap comes from.
Binary vs. SI: which standard should you use?
Use the binary standard (1,024) when: reading file sizes shown by Windows Explorer, macOS Finder, or Linux file managers; working with RAM capacity (always binary); or comparing sizes within one operating system. Use the SI standard (1,000) when: reading the advertised capacity of hard drives, SSDs, USB sticks, or memory cards; working with network bandwidth, which telecoms measure in SI units (Mbps means 1,000,000 bits per second); or following the IEC 80000-13 standard used in technical specifications. If precision matters, the IEC introduced MiB (mebibyte) for the binary 1,024-based unit and kept MB for the SI 1,000-based unit, but most everyday usage still uses MB for both.
Quick reference: unit hierarchy for digital storage
The standard chain in binary is: 8 bits = 1 byte, 1,024 bytes = 1 KB, 1,024 KB = 1 MB, 1,024 MB = 1 GB, 1,024 GB = 1 TB. In SI the divisors are all 1,000. This calculator converts between KB and MB and also shows the byte and GB equivalents so you can see the full picture at once.
Common KB to MB conversions (binary: 1 MB = 1,024 KB)
| Kilobytes (KB) | Megabytes (MB) | Typical use case |
|---|---|---|
| 1 | 0.000977 MB | Single plain-text page |
| 10 | 0.009766 MB | Small HTML file or script |
| 100 | 0.097656 MB | Compressed thumbnail image |
| 256 | 0.250000 MB | Small program or plugin |
| 512 | 0.500000 MB | Medium-quality photo |
| 1024 | 1.000000 MB | Good-quality JPEG photo |
| 2048 | 2.000000 MB | High-quality JPEG or short MP3 |
| 5120 | 5.000000 MB | Full-quality DSLR photo (RAW) |
| 10240 | 10.000000 MB | Short video clip or album cover art |
| 51200 | 50.000000 MB | Standard app download |
| 102400 | 100.000000 MB | HD video (1-2 minutes) |
| 524288 | 512.000000 MB | Large game level or database |
| 1048576 | 1,024.000000 MB | Approx. 1 GB |
These are the values your operating system uses when displaying file sizes.
Frequently asked questions
How many KB are in 1 MB?
It depends on the standard. The binary standard used by operating systems defines 1 MB as exactly 1,024 KB. The SI decimal standard used by storage manufacturers defines 1 MB as exactly 1,000 KB. Select the standard in our converter to get the right number for your context.
Is 1,024 KB equal to 1 MB or 1 MiB?
Strictly speaking, 1,024 KB (where KB = 1,024 bytes) equals 1 MiB (mebibyte). The IEC introduced MiB to remove ambiguity. In practice most people and most operating systems still write MB when they mean the binary 1,024-based unit. Our converter uses the terms KB and MB in the everyday sense and lets you pick which divisor applies.
How do I convert MB back to KB?
Switch the "Conversion direction" selector to "MB to KB (reverse)" and enter your megabyte value. The calculator multiplies by 1,024 (binary) or 1,000 (SI) to give you kilobytes, plus the byte and GB equivalents.
What is the difference between KB and kB?
In strict SI notation, K (uppercase) is reserved for kelvin and k (lowercase) is the kilo prefix, so kB is technically correct for kilobyte. In computing, KB with an uppercase K is the most common informal spelling and is understood to mean kilobyte in almost all contexts. Our converter uses KB following common computing usage.
Why does Windows show a different file size than macOS?
Older versions of Windows reported sizes in binary units but labelled them GB/MB (e.g. a file of 1,073,741,824 bytes would show as "1 GB"). macOS has consistently used the SI decimal meaning since OS X 10.6 Snow Leopard (2009), so the same file appears as "1.07 GB". Modern Windows versions behave similarly to macOS. If you see a discrepancy, check which OS version is involved and use the binary or SI toggle in our converter accordingly.
How big is 1 MB in practical terms?
One megabyte (binary, 1,048,576 bytes) holds roughly: 1 minute of MP3 audio at 128 kbps, one good-quality JPEG photo from a smartphone, about 500 pages of plain text, or a small PDF document. For comparison, a full HD movie is typically 1,000 to 4,000 MB (1-4 GB), and a single email with a photo attachment is usually 1-5 MB.