GB to TB converter, and why a 1 TB drive shows less.

To convert GB to TB, divide by 1,000. So 2,000 GB is 2 TB, 500 GB is 0.5 TB and 250 GB is 0.25 TB. A drive sold as 1 TB holds 1,000,000,000,000 bytes, which a system that counts in 1,024s calls about 931.32 GiB.

How to use the converter

1. Type the amount in the Gigabytes (GB) box. A decimal such as 2.5 or a fraction such as 3/4 works.
2. The big result shows Terabytes (TB). Use Decimals in the side column to fix the number of places.
3. The first card reads your number as GiB and shows TiB. The others give the same size in GiB, TiB and MB.
4. Type in the second box, or press the swap button, to convert terabytes to gigabytes instead.
5. Click a row in Common values to load it. Copy result, Copy link, Copy table and Print chart keep the answer. Start again resets the box.

Where the missing space goes

Nothing is missing. The seller counts in powers of ten: 1 TB = 10¹² bytes. A tool that counts in powers of two uses the tebibyte (1,099,511,627,776 bytes) and the gibibyte (1,073,741,824 bytes), so the same drive is 10¹² ÷ 2³⁰ = 931.32 GiB, or 0.9095 TiB. If it prints those numbers with the letters GB or TB, it looks like space has gone. The NIST page on prefixes for binary multiples gives the binary names. Read 24 Oct 2026.

Drive sizes, in TB and in TiB

Worked examples

• Four 500 GB drives. 4 × 500 = 2,000 GB = 2 TB.
• A 3,500 GB photo library. 3,500 ÷ 1,000 = 3.5 TB.
• A 12 TB drive in GB. Press the swap button and type 12: 12,000 GB.
• A 750 GB drive. 0.75 TB, or 698.5 GiB.
• The binary way. 2,048 GiB is exactly 2 TiB.

Planning space with the numbers

If you have 600 GB of files and a 1 TB drive, the files take 0.6 TB by the seller's count. Use one system for the whole calculation. Mix them and you will think you have 7 percent more room than you do. Add a margin for the system and for deleted file recovery.

Reading a spec sheet

Cloud plans, laptops and drives all list storage in GB or TB, but they do not always say which system they use. A rule that works: if a number comes from a seller or a cloud bill, assume powers of ten. If it comes from a file manager or a command line tool, check whether it says GiB or TiB. When you add up several drives, add the GB figures first and divide by 1,000 only at the end, so rounding does not pile up. Three 750 GB drives make 2.25 TB.

Where the numbers come from

Prefixes follow the NIST page on prefixes for binary multiples: giga and tera are powers of ten, gibi and tebi are powers of two. Checked 24 Oct 2026. The converter uses exact fractions and rounds only the last digit.

Related pages: MB to GB, KB to MB, Mbps to MB/s and Unit converter.