MB uses 1,000,000 bytes; MiB uses 1,048,576 bytes. The 4.9% gap is small but causes visible discrepancies in RAM readouts, file system reports, and download progress bars when software mixes decimal and binary conventions.
Last updated: May 2026
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How to Convert MB to MIB
1 MiB = 1,048,576 bytes; 1 MB = 1,000,000 bytes. To convert MB to MiB, divide by 1.048576. At 100 MB: 95.37 MiB. At 512 MB: 488.28 MiB. For the reverse (MiB to MB), multiply by 1.048576. At gigabyte scale the difference grows, so the GB to GiB converter handles drive capacity and OS storage reporting.
Example: 100 MB ÷ 1.049 = 95.37 MiB
Conversion Table
MB
MIB
1 mb
0.9537 mib
2 mb
1.9074 mib
5 mb
4.7685 mib
10 mb
9.537 mib
20 mb
19.074 mib
50 mb
47.685 mib
100 mb
95.37 mib
250 mb
238.425 mib
500 mb
476.85 mib
1000 mb
953.7 mib
Where the 4.9% gap becomes visible
The MB vs MiB difference is small enough to ignore for rough estimates but large enough to create visible discrepancies in several everyday situations. Much of the confusion persists because Windows has historically used the binary size (1 MB = 1,048,576 bytes) while labelling files and drives with the decimal abbreviation MB.
Windows File Explorer: reports sizes using 1 KB = 1,024 bytes (binary) but displays the result as MB. A file containing exactly 1,000,000,000 bytes (1 decimal GB) shows as "953 MB" in Explorer because 1,000,000,000 / 1,048,576 = 953.7 MiB.
Hard drive capacity: drive manufacturers define 1 TB as exactly 1,000,000,000,000 bytes. Windows interprets that using binary GiB and shows the same drive as 931 GB. The drive is not short-changed; the label applies a different definition of the unit.
RAM: physical memory is always addressed in binary. A "8 GB" RAM kit holds 8 GiB = 8,589,934,592 bytes. Task Manager shows 8.0 GB because it reads GiB and applies the MB label, which is technically incorrect but consistent with Windows convention.
Download progress bars: browsers such as Chrome report file sizes in decimal MB. A 100 MB download file can appear as "95.4 MiB received" in a download manager that uses binary mebibytes for the same transfer.
Linux and macOS have moved toward labelling correctly: Ubuntu Disk Utility shows drives in GiB; macOS shows storage in decimal GB. When switching between operating systems, the same file can appear to change size because the unit definition changed, not the byte count.
Frequently Asked Questions
Windows says I have 8 GB RAM but my machine has 8192 MB installed. Is some RAM missing?
No. 8192 MB (using 1 MB = 1,048,576 bytes, as RAM manufacturers do) equals exactly 8 GiB. Windows displays RAM in binary GiB. Since 8 GiB = 8,589,934,592 bytes, and hardware reports in binary units too, everything aligns. The confusion happens when people mix the decimal MB label from old-style documentation with the binary GiB Windows displays.
Why do download speeds show MB/s while disk tools show MiB/s?
Networking equipment uses decimal megabytes (MB, 1,000,000 bytes). Storage and many operating systems use binary mebibytes (MiB, 1,048,576 bytes). When your connection downloads at 100 MB/s, a storage tool reporting in MiB would show approximately 95.4 MiB/s. If your download progress shows slower than your advertised speed, check whether the software is using MB or MiB before concluding there is a problem.
Why does software show MB when it technically means MiB?
Historically, "megabyte" was used loosely for both 1,000,000 and 1,048,576 bytes. The IEC standardized "mebibyte" (MiB) for binary megabytes in 1998, but software adoption has been slow. Many programs (including file managers and RAM monitors) still display "MB" when they technically mean "MiB." This converter handles both interpretations.
Why does my 1 TB hard drive only show 931 GB in Windows?
Drive manufacturers define 1 TB as exactly 1,000,000,000,000 bytes (decimal). Windows calculates available space by dividing that byte count by 1,073,741,824 (1 binary GiB), which gives 931.3. So Windows reports 931 GB even though the drive contains the full 1,000,000,000,000 bytes the manufacturer claimed. Neither figure is wrong; they are measuring the same bytes with different unit definitions. To compare drive sizes fairly, always use the same unit system: decimal GB for manufacturer claims, or binary GiB for what Windows reports.
Which applications use MB (decimal) and which use MiB (binary) for file sizes?
In practice: hard drive and flash storage manufacturers use decimal MB. Network speeds (ISPs, Wi-Fi specs) use decimal Mbps and MB/s. Cloud storage providers (Google Drive, Dropbox, OneDrive) now use decimal GB. On the binary side: Windows File Explorer reports in MiB but labels them MB; older Linux file managers (Nautilus before GNOME 3.6) did the same. Modern Ubuntu uses correct GiB/MiB labels. macOS switched from binary to decimal labelling in 10.6 Snow Leopard. If precision matters, check which convention the specific tool uses before comparing numbers across applications.
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