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To convert gigabytes to gibibytes, multiply GB by 0.9313225746. To convert megabits per second to megabytes per second, divide Mbps by 8. For example, 100 GB is about 93.1323 GiB, while 100 Mbps is 12.5 MB/s. These are unit conversions—not predictions of actual download speed.
GB and GiB measure different byte counts
A gigabyte (GB) uses the decimal prefix giga: 1 GB equals 1,000,000,000 bytes. A gibibyte (GiB) uses the binary prefix gibi: 1 GiB equals 230 bytes, or 1,073,741,824 bytes. NIST defines these units and distinguishes SI prefixes from binary prefixes in its binary-prefix reference and SP 330, section 3.
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Because a GiB contains more bytes than a GB, a quantity expressed in GiB is numerically smaller than the same number of bytes expressed in GB. The relationship is 1 GB ≈ 0.9313226 GiB, or 1 GiB = 1.073741824 GB.
Convert GB to GiB
Divide the number of bytes in the GB value by the number of bytes in a GiB:
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GiB = GB × 1,000,000,000 ÷ 1,073,741,824
For everyday calculations, use the rounded multiplier:
GiB ≈ GB × 0.9313225746
| GB | GiB (approximately) |
|---|---|
| 1 | 0.9313 |
| 100 | 93.1323 |
To convert in the opposite direction, multiply GiB by 1.073741824:
GB = GiB × 1.073741824
Convert Mbps to MB/s
Mbps means megabits per second; MB/s means megabytes per second. The lowercase b stands for bit, while uppercase B stands for byte. One byte is eight bits, so for decimal Mbps and MB/s, divide by 8:
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To convert MB/s back to Mbps, multiply by 8. NIST defines the byte as eight bits and notes that telecommunications usage of megabit per second means 106 bits per second; its GiB glossary entry gives the binary byte definition. The decimal mega prefix is also described in NIST SP 330, section 3.
| Connection rate | Decimal data rate equivalent |
|---|---|
| 8 Mbps | 1 MB/s |
| 100 Mbps | 12.5 MB/s |
| 500 Mbps | 62.5 MB/s |
| 1,000 Mbps | 125 MB/s |
Why a download may be slower than the conversion
Dividing an advertised Mbps rate by 8 changes the unit; it does not guarantee that a download will reach the resulting MB/s figure. The formula says what the rate would be if the full stated bit rate were available for data at that moment. Actual transfer speed can differ because of network and protocol effects, as well as conditions along the connection and at the download source.
Keep the conversion separate from a speed test: use Mbps ÷ 8 for the theoretical decimal MB/s equivalent, then treat a measured download rate as an observed result rather than a contradiction of the arithmetic.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Check the units before comparing values
- Prefix: GB is decimal (109 bytes); GiB is binary (230 bytes).
- Bit or byte: Mbps uses bits; MB/s uses bytes. The factor between them is 8.
- Time: The “/s” remains seconds in both Mbps and MB/s.
- Rounding: Label approximate results and retain enough digits for the task.
These definitions avoid treating GB and GiB as interchangeable or confusing a bit rate with a byte rate. NIST advises using SI prefixes for powers of 10 and binary-prefix names for powers of 2.
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