Bytes to MB Converter

How to convert bytes to MB

To convert bytes to MB, divide by 1,000,000. A file of 2,500,000 bytes is 2.5 MB. In the binary system, divide by 1,048,576 instead, which makes the same file about 2.38 MB. That's exactly the gap you see between a file's exact size and the rounded size Windows prints next to it.

Byte counts are the most exact way to check an upload limit. A form that rejects anything over 2 MB is ultimately checking bytes, so converting the exact figure removes the guesswork.

bytes to MB formula

• Decimal: MB = bytes / 1,000,000 (and KB = bytes / 1000)
• Binary: MiB = bytes / 1,048,576 (and KiB = bytes / 1024)

Example: 3,145,728 bytes / 1,048,576 = 3 MiB, or 3.15 MB in decimal.

Why are there two answers: 1000 or 1024?

Computers count in powers of two, so early on a kilobyte was taken to mean 1,024 bytes. Standards bodies later fixed the prefixes to their usual meaning, kilo for 1,000, and added separate names for the binary units: KiB, MiB and GiB. Drive makers, network figures and macOS use the decimal units. Windows File Explorer still divides by 1024 but prints KB, MB and GB.

That's why a 1 TB drive shows about 931 GB in Windows. Nothing is missing; it's the same number of bytes counted two ways. For a longer explanation, read how many KB are in a MB and how many MB are in a GB.

File too big for an upload limit?

If the conversion shows your file is over the limit, shrink it to a set size instead of guessing. Image Compressor takes photos down to a target such as 50 KB or 200 KB, and Compress PDF does the same for documents. Aim slightly under the limit, for example 190 KB for a 200 KB cap, so the file passes whichever way the site counts.