Is a Gigabyte 1000 or 1024 Megabytes?

Technically, 1 Gigabyte (GB) is 1,000 Megabytes (MB) in storage and networking (this is the decimal system, base-10).

However, in computer memory (RAM), 1 Gigabyte is usually considered 1,024 Megabytes (this is the binary system, base-2).

Proof and Evidence

1. Storage devices (hard drives, SSDs, USBs):

• Manufacturers use decimal measurements.
• 1 GB = 1,000 MB = 1,000,000 KB = 1,000,000,000 bytes.
• Example: A 500 GB hard drive is marketed as 500 × 1,000,000,000 bytes.

2. Computer memory (RAM, operating systems like Windows):

• Computers use binary measurements.
• 1 GB = 1,024 MB = 1,048,576 KB = 1,073,741,824 bytes.
• Example: In Windows, 8 GB of RAM shows as about 8 × 1,024 MB.

Official Standards

• International System of Units (SI): Defines giga as 1,000,000,000 (decimal).
• IEC Standard (1998): Introduced Gibibyte (GiB) for binary:
  • 1 GiB = 1,024³ bytes = 1,073,741,824 bytes.
  • 1 GB (decimal) ≠ 1 GiB (binary).

Simple Summary

Here is reliable reference you can check:

Wikipedia – Gigabyte – Explains both decimal (1,000 MB) and binary (1,024 MB) usage – Wikipedia – Gigabyte.