The Core of the Confusion: 1000 vs. 1024

The confusion around file size conversion stems from two different number systems being used: decimal (base-10) and binary (base-2).

  • Decimal (Base-10): This is the system we use in everyday life. In this system, "kilo" means 1,000, "mega" means 1 million, and "giga" means 1 billion. Hard drive manufacturers and marketers use this system because it results in round, larger-sounding numbers.
    (e.g., 1 Gigabyte (GB) = 1,000 Megabytes (MB))
  • Binary (Base-2): Computers operate on a binary system. In this world, everything is based on powers of 2. A kilobyte is actually 2¹⁰, which is 1,024. This is the system your operating system (like Windows or macOS) uses to calculate file sizes.
    (e.g., 1 Gibibyte (GiB) = 1,024 Mebibytes (MiB))

The Golden Rule: When you are dealing with computer files, memory, and storage capacity as reported by your OS, you should almost always use the 1024 conversion factor for accuracy.

How to Convert MB to GB

Since a Gigabyte (GB) is a larger unit than a Megabyte (MB), you need to divide the number of MB by 1024 to get the equivalent number of GB.

The Formula:

Number of GB = Number of MB / 1024

Example Calculation:

You have a collection of photos that totals 4,500 MB. How many GB is that?

Calculation:
4,500 MB / 1024 = 4.39 GB

So, your photo collection takes up 4.39 GB of space.

How to Convert MB to TB

Converting from Megabytes (MB) to Terabytes (TB) is a bigger jump. Since 1 TB = 1024 GB, and 1 GB = 1024 MB, you need to divide by 1024 twice.

The Formula:

Number of TB = (Number of MB / 1024) / 1024

Or, more simply:

Number of TB = Number of MB / 1,048,576 (since 1024 x 1024 = 1,048,576)

Example Calculation:

You have a large video archive totaling 2,000,000 MB. How many TB is that?

Calculation:
2,000,000 MB / 1,048,576 = 1.91 TB

Your video archive has a total size of 1.91 TB.

Quick Conversion Reference Chart

Here’s a simple chart to help you visualize the relationships between these units.

Unit Equivalent in MB Equivalent in GB Equivalent in TB
1 MB 1 ~0.000977 ~0.000000954
1 GB 1,024 1 ~0.000977
1 TB 1,048,576 1,024 1

Final Thoughts: Context is Key

Understanding the 1024 conversion factor is the key to correctly converting digital storage units. While manufacturers will continue to use the base-10 (1000) system for marketing, your computer will always use the binary (1024) system for its calculations. By using 1024 in your own conversions, you'll get a real-world figure that matches what you see on your screen, finally solving the mystery of the "missing" storage space.