How many bytes are in a megabyte?

In the SI decimal standard used by storage manufacturers, 1 MB = 1,000,000 bytes (10^6). In the IEC binary standard used by most operating systems, 1 MiB = 1,048,576 bytes (2^20). The difference is about 4.9%.

Why does Windows show a different MB than the manufacturer?

Windows uses binary units (powers of 1024) but historically labeled them "MB." A file that is 1,000,000 bytes appears as roughly 0.954 MB in Windows. Manufacturers count in SI decimal, so 1 MB is exactly 1,000,000 bytes on the box.

When should I use MB versus MiB?

Use MB (SI) for disk capacity, network speeds, and anything labeled by hardware or ISP specs. Use MiB (binary) when working with RAM, OS file-system reports, or any context where the system uses powers of 1024.

Is 1 MB = 1024 KB or 1000 KB?

Under SI: 1 MB = 1000 KB = 1,000,000 bytes. Under IEC binary: 1 MiB = 1024 KiB = 1,048,576 bytes. Both definitions are correct — they just apply to different contexts.

How accurate is this converter for large byte values?

Calculations use JavaScript 64-bit floating-point arithmetic, which is accurate to about 15–16 significant digits. For any practical file size (even multi-petabyte values) the precision is more than sufficient.

Bytes to Megabytes Converter

Name: Bytes to Megabytes Converter
Availability: InStock
Author: Nham Vu

Enter a byte count and instantly see the equivalent in megabytes (MB) and mebibytes (MiB), plus a reference table for common sizes.

Enter Bytes

Number of bytes

MB (SI): 1 MB = 1,000,000 bytes — used by storage manufacturers, ISPs, file transfers.

MiB (binary): 1 MiB = 1,048,576 bytes — used by OS file explorers and RAM specs.

Results

Enter a byte value and click Convert.

Common File Size Reference

Description	Bytes	MB (SI)	MiB (Binary)
1 KB (SI)	1,000	0.001 MB	0.000954 MiB
1 KiB (binary)	1,024	0.001024 MB	0.000977 MiB
Average JPEG photo	3,000,000	3 MB	2.861 MiB
MP3 song (~3 min)	5,000,000	5 MB	4.768 MiB
1 MB (SI)	1,000,000	1 MB	0.953674 MiB
1 MiB (binary)	1,048,576	1.048576 MB	1 MiB
HD video (1 min, 720p)	100,000,000	100 MB	95.367 MiB
Typical app install	500,000,000	500 MB	476.837 MiB
1 GB (SI)	1,000,000,000	1,000 MB	953.674 MiB

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Summary

Enter a byte count and instantly see the equivalent in megabytes (MB) and mebibytes (MiB), plus a reference table for common sizes.

How it works

Enter any number of bytes in the input field.
The converter divides by 1,000,000 to produce the SI megabyte (MB) result.
It also divides by 1,048,576 to produce the binary mebibyte (MiB) result.
Results are shown to up to 8 significant decimal places.
Use the copy button next to any result to grab the value.
The reference table below shows common file sizes for quick comparison.

Use cases

Check how many MB a file will appear as on a storage device or download manager.
Convert API response sizes from bytes to human-readable megabytes for logging.
Compare OS-reported file sizes (binary MiB) with storage-spec sizes (SI MB).
Calculate data transfer costs when providers bill in MB increments.
Translate raw byte counts from database fields into user-friendly displays.
Verify that a backup fits within a megabyte quota before uploading.

Frequently Asked Questions

Last updated: 2026-07-22 · Reviewed by Nham Vu