MB to MiB Converter
A megabyte (MB) is 1,000,000 bytes (decimal SI). A mebibyte (MiB) is 1,048,576 bytes (binary IEC). One MB equals approximately 0.9537 MiB.
Formula
MiB = MB × 0.95367431640625
Reverse:
MB = MiB × 1.048576
Formula variables
- MB — size in decimal megabytes. 1 MB = 10⁶ bytes = 1,000,000 bytes.
- MiB — size in binary mebibytes. 1 MiB = 2²⁰ bytes = 1,048,576 bytes.
- 0.95367431640625 — the ratio 10⁶ / 2²⁰, exact.
Worked Examples
Example 1: 1 MB to MiB
- 1 MB = 1,000,000 bytes.
- 1 MiB = 1,048,576 bytes.
- 1,000,000 ÷ 1,048,576 = 0.95367431640625.
- Result: 1 MB ≈ 0.9537 MiB.
Example 2: 100 MB to MiB
- 100 MB = 100,000,000 bytes.
- 100,000,000 ÷ 1,048,576 = 95.367431640625.
- Result: 100 MB ≈ 95.3674 MiB.
Example 3: 1000 MB (1 GB) to MiB
- 1000 MB = 1 GB = 1,000,000,000 bytes.
- 1,000,000,000 ÷ 1,048,576 = 953.67431640625.
- Result: 1000 MB (1 GB) ≈ 953.674 MiB.
Common Conversion Table
| MB (SI) | MiB (IEC) |
|---|---|
| 1 | 0.953674 |
| 10 | 9.536743 |
| 100 | 95.367432 |
| 250 | 238.418579 |
| 500 | 476.837158 |
| 1000 | 953.674316 |
| 2000 | 1907.348633 |
| 5000 | 4768.371582 |
Why the Difference Matters
This is the single most common source of confusion in consumer storage. Drive manufacturers specify capacity in decimal SI units (MB, GB, TB). Most operating systems display capacity in binary IEC units (MiB, GiB, TiB) — but label them with the SI prefixes, which is inconsistent.
A drive advertised as "1 TB" contains 1,000,000,000,000 bytes. In binary, that is 1,000,000,000,000 ÷ 1,099,511,627,776 ≈ 0.9095 TiB, or about 931 GiB. The operating system may show "931 GB", which is 931 GiB mislabeled.
Decimal vs. Binary — The Full Picture
| Prefix | Decimal (SI) | Binary (IEC) | Ratio |
|---|---|---|---|
| kilo/kibi | 1,000 bytes | 1,024 bytes | 1.024 |
| mega/mebi | 10⁶ bytes | 2²⁰ bytes | 1.048576 |
| giga/gibi | 10⁹ bytes | 2³⁰ bytes | 1.073741824 |
| tera/tebi | 10¹² bytes | 2⁴⁰ bytes | 1.099511627776 |
| peta/pebi | 10¹⁵ bytes | 2⁵⁰ bytes | 1.125899906843 |
Real-World Uses
- Storage capacity: Understanding why a "500 GB" SSD shows up as roughly 465 GiB in some tools.
- Networking: Internet speeds are often quoted in Mbps (decimal). File sizes are quoted in MB or MiB. The mismatch matters when estimating download times.
- Software development: Correctly distinguishing MB and MiB in code and documentation avoids subtle bugs.
- Cloud billing: Some providers bill by GB (decimal) while others bill by GiB (binary).
Unit Definitions
Megabyte (MB)
A decimal unit of digital information equal to exactly 1,000,000 bytes, defined by the SI prefix "mega" (10⁶). It is the correct term for storage capacity in SI-consistent contexts and is the standard used by drive manufacturers.
Mebibyte (MiB)
A binary unit of digital information equal to exactly 1,048,576 bytes (2²⁰). Introduced in 1998 by the IEC (and later standardized in IEEE 1541-2002) to disambiguate the word "megabyte", which had previously been used for both values.
Accuracy and Rounding
Because 1 MiB = 1,048,576 bytes exactly and 1 MB = 1,000,000 bytes exactly, the ratio 1,000,000 ÷ 1,048,576 is a precise rational number. Displayed values are rounded to significant figures appropriate to the input magnitude.
Related Converters
Frequently Asked Questions
What is the difference between MB and MiB?
MB (megabyte) is a decimal SI unit equal to 1,000,000 bytes. MiB (mebibyte) is a binary IEC unit equal to 1,048,576 bytes (2²⁰). One MB equals approximately 0.9537 MiB.
How do you convert MB to MiB?
Multiply the MB value by 0.95367431640625. For example, 100 MB × 0.95367431640625 = 95.3674 MiB.
Why does a 1 TB drive show as 931 GB?
Manufacturers use decimal SI (1 TB = 1,000,000,000,000 bytes). Some operating systems display binary IEC (1 TiB = 1,099,511,627,776 bytes). 1,000,000,000,000 ÷ 1,099,511,627,776 ≈ 0.9095 TiB ≈ 931 GiB.
Which is bigger, MB or MiB?
MiB is bigger. One MiB = 1,048,576 bytes, while one MB = 1,000,000 bytes. So one MiB is about 4.86% larger than one MB.
Why do we have two different systems?
Before 1998, "megabyte" was ambiguous — some used it for 1,000,000 bytes and some for 1,048,576 bytes. The IEC introduced mebibyte (MiB) to disambiguate. However, the older usage persists in marketing and everyday language.