💾 Data storage
TB to GB Converter
Enter terabytes and press Convert to get gigabytes. 1 TB to GB is 1,000 in decimal terms. 1 TB is 1000 GB in decimal and 931.32 GiB in Windows.
About the TB to GB Converter
The terabyte is where the decimal-versus-binary gap starts to look like real missing capacity: 1 TB is 1000 GB as sold, but 1,000,000,000,000 bytes is only 931.32 GiB. A 2 TB drive therefore reports 1.81 TB in Windows — the same physical drive, measured twice.
Backup planning is where the conversion matters. If you size a NAS by adding up decimal terabytes, plan for roughly 7% less usable space once the operating system has done its own binary arithmetic.
How the calculation works
- 1 TB = 1000 GB (decimal)
- 1 TiB = 1024 GiB (binary)
- Decimal TB ÷ 1.099511627776 = binary TiB
Reference values
| Terabytes | Gigabytes | Binary TiB |
|---|---|---|
| 1 TB | 1,000 GB | 0.909 TiB |
| 2 TB | 2,000 GB | 1.819 TiB |
| 4 TB | 4,000 GB | 3.638 TiB |
| 8 TB | 8,000 GB | 7.276 TiB |
| 10 TB | 10,000 GB | 9.095 TiB |
| 16 TB | 16,000 GB | 14.552 TiB |
| 20 TB | 20,000 GB | 18.190 TiB |
Worked examples
- A 4 TB NAS holds 4,000 GB decimal, which a file manager shows as 3.64 TiB.
- A 14 TB drive is 14,000 GB, enough for roughly 350 hours of 4K video at 40 GB an hour.
- 500 GB is 0.5 TB, so two 500 GB drives equal one 1 TB drive in capacity terms.
Checking the answer by hand
Multiply by 1,000 for decimal gigabytes and divide the decimal terabyte figure by 1.0995 to get TiB. A 2 TB drive should read about 1.82 TiB; if yours reads 1.86, it is a 2,048 GB drive, not a 2 TB one.
Common mistakes
- Planning a backup by adding decimal terabytes and expecting that much usable space.
- Confusing a terabyte with a tebibyte when comparing drive prices — the 9.95% gap changes the cost per gigabyte.
- Assuming RAID gives full capacity. Mirroring halves it, and parity costs one drive's worth.
A last check on the numbers: 37 Terabyte (10¹²) works out to 37,000 Gigabyte (10⁹), and reversing that with the same factor brings you back to 37 Terabyte (10¹²). Because Terabyte (10¹²) to Gigabyte (10⁹) is a single multiplication, any tool that gives a different figure for the same input is rounding somewhere in the middle rather than only at the end.