A gigabyte is defined as 1,000 megabytes under the decimal (storage-industry) convention used here.
How it works
Dividing megabytes by 1,000 gives gigabytes; multiplying gigabytes by 1,000 gives megabytes back. Type into either field and the other updates instantly.
What this does not include
This does not include the binary (1024-based) convention some operating systems use for the same unit names — for both conventions side by side, use this site’s full data storage converter instead.
How to use this calculator
- Enter a value in either megabytes or gigabytes — the other field fills in automatically.
Frequently asked questions
Why do some tools show a different MB-to-GB ratio?
Operating systems sometimes use the binary convention (1024 MB per GB) instead of the decimal convention (1000 MB per GB) used here — both are valid, just different standards.
Which convention do storage manufacturers use?
The decimal (1000-based) convention, matching this calculator, which is why a “1 TB” hard drive shows less capacity than expected under an operating system using the binary convention.
Where is this conversion most commonly needed?
Comparing file sizes, storage plans, and download sizes across different display conventions.
