How to Convert GB to MB (and MB to GB) - Data Storage Explained
Confused about gigabytes and megabytes? This guide explains exactly how to convert between GB and MB, the difference between decimal and binary prefixes, and real-world examples.
GB vs MB — What's the Difference?
Gigabytes (GB) and megabytes (MB) are both units of digital data storage. The difference is size: one gigabyte is much larger than one megabyte. Understanding the relationship between them helps you make sense of file sizes, internet speeds, storage capacity, and data plan limits.
The Conversion: How Many MB in a GB?
This depends on whether you're using decimal (SI) or binary (IEC) definitions — and they give different answers.
Decimal (used by storage manufacturers and internet providers)
1 GB = 1,000 MB
Storage device manufacturers use this definition. When a hard drive or USB drive advertises "500 GB", they mean 500,000 MB in decimal terms.
Binary (used by operating systems)
1 GiB (gibibyte) = 1,024 MiB (mebibytes)
Windows, macOS, and Linux report file sizes using binary units. This is why a "500 GB" hard drive shows up as about 465 GB in Windows — the OS is using binary calculation.
Simple Conversion Examples
| Gigabytes (GB) | Megabytes (MB) — Decimal |
|---|---|
| 0.5 GB | 500 MB |
| 1 GB | 1,000 MB |
| 2 GB | 2,000 MB |
| 5 GB | 5,000 MB |
| 10 GB | 10,000 MB |
| 50 GB | 50,000 MB |
| 1 TB | 1,000,000 MB |
Real-World File Size Examples
- A typical MP3 song: 3–5 MB
- A high-quality photo: 3–10 MB
- A 1-hour HD video: 1–2 GB
- A standard DVD movie: 4.7 GB
- A modern video game: 30–100 GB
- 1 hour of 4K video: 45–100 GB
Mobile Data Plans — Understanding Your Allowance
Mobile data plans are sold in GB. Here's what common allowances can realistically cover:
- 1 GB/month: Light use — emails, occasional browsing, some social media
- 5 GB/month: Moderate use — regular browsing, music streaming, video calls
- 20 GB/month: Heavy use — daily video streaming, large file downloads
- Unlimited: No restrictions — full video streaming, gaming, hotspot use
Convert Any Data Unit Instantly
Use our free data storage converter to convert between bits, bytes, kilobytes, megabytes, gigabytes, terabytes and more.