# Gigabytes to megabytes converter

> Convert gigabytes to megabytes (GB to MB) with the exact factor, a conversion chart and worked steps.

Interactive version: https://www.calcopenly.com/conversion/gb-to-mb
Subject: Unit converters

Gigabytes may describe a data plan, a collection of files or a drive partition. Converting that allowance helps compare it with a differently labelled quota. Keep decimal GB separate from GiB and distinguish storage capacity from a transfer rate.

One gigabyte is exactly 1,000 megabytes, so 2 GB is 2,000 MB. To convert GB to MB, multiply by 1,000; to convert back, multiply by 0.001.

Storage makers use decimal prefixes, so 1 GB is 1,000 MB; some operating systems report binary units (1 GiB = 1,024 MiB). Because both units are defined exactly, the factor above is exact and the results here carry no conversion error.

## Inputs

- **Gigabytes (GB)**

## Results

- Megabytes (MB) — main result
- Conversion
- 1 MB in gigabytes (GB)

## Formula

$$
\text{megabytes} = \text{gigabytes} \times 1{,}000
$$

## Worked examples

### 2 GB to MB

- Gigabytes (GB): 2 GB
- **Megabytes: 2,000 MB**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 4 GB to MB

- Gigabytes (GB): 4 GB
- **Megabytes: 4,000 MB**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

### 64 GB to MB

- Gigabytes (GB): 64 GB
- **Megabytes: 64,000 MB**
- Checked against: Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions)

## Questions

### When would I convert GB to MB?

Gigabytes may describe a data plan, a collection of files or a drive partition. Converting that allowance helps compare it with a differently labelled quota. Keep decimal GB separate from GiB and distinguish storage capacity from a transfer rate.

### How many megabytes are in a gigabyte?

One gigabyte is exactly 1,000 megabytes. Storage makers use decimal prefixes, so 1 GB is 1,000 MB; some operating systems report binary units (1 GiB = 1,024 MiB).

### How do you convert GB to MB?

Multiply the number of gigabytes by 1,000. For example, 2 GB × 1,000 = 2,000 MB. To go the other way, divide by 1,000.

### Why does my computer show less space than the drive's label?

Drive makers count 1 GB as 1,000,000,000 bytes, while Windows and some other systems count in binary units of 1,073,741,824 bytes but still label them GB. A 1 TB drive therefore appears as about 931 GB (really 931 GiB).

### How accurate is the gigabytes to megabytes converter?

Accuracy depends on your inputs and the method's assumptions. Decimal arithmetic uses 50 significant digits, but estimates, numerical methods and source data can be less precise; the displayed rounding does not remove those limits. It is checked against 3 worked examples whose answers come from independent sources; for example, “2 GB to MB” is checked against Exact-fraction computation from the legal unit definitions (scripts/gen-pairs.py, Python fractions).

### Where does the method come from?

NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B; NIST Handbook 44, Appendix C: General tables of units of measurement; BIPM, The International System of Units (SI Brochure), 9th edition.

## Sources

- [NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B](https://www.nist.gov/pml/special-publication-811)
- [NIST Handbook 44, Appendix C: General tables of units of measurement](https://www.nist.gov/pml/weights-and-measures/publications/nist-handbooks/handbook-44)
- [BIPM, The International System of Units (SI Brochure), 9th edition](https://www.bipm.org/en/publications/si-brochure)