What is a Megabyte?

The megabyte (MB) equals 1,000 kilobytes (1,000,000 bytes decimal, or 1,048,576 bytes binary as MiB). It is the everyday unit for image files, MP3 songs, and small documents on personal computers. A high-quality JPEG photograph is 2–10 MB, an MP3 song is 3–10 MB, a Microsoft Word document might be 0.05–5 MB, and a typical e-book is under 5 MB. Older USB flash drives and CDs hold hundreds of MB (a CD is 700 MB). Mobile data plans were originally measured in MB before gigabyte plans became standard. The megabyte relates to the kilobyte (1,000 KB = 1 MB), the gigabyte (1,000 MB = 1 GB), and the megabit (1 MB = 8 Mbit). Internet connection speeds are usually rated in Mbps (megabits per second), distinct from MBps (megabytes per second): 100 Mbps = 12.5 MBps.

Visual reference for how the megabyte relates to other data units. Each row links to the full converter for that pair.

• Photo and image file sizes
• MP3 and audio files
• Small video clips

• ✓SI: 1 MB = 1000 KB = 1,000,000 B.
• ✓Binary MiB = 1,048,576 B — 4.86% larger.
• ✓HD drives, networks, SSDs: SI MB.

• ✗Mixing MB and MiB without noting the difference (~5%).
• ✗Confusing MB (storage) with Mb (megabit, 1/8).
• ✗Assuming 1 GB = 1000 MB always — correct in SI; binary it's 1024.