GB to TB Converter
Convert gigabytes to terabytes and understand why your 1 TB drive shows only 931 GB in Windows. Binary (1,024 GB = 1 TB) vs decimal (1,000 GB = 1 TB) — both are correct, just different standards.
GB to TB Converter
Convert gigabytes to terabytes with decimal (SI) and binary (IEC) conversion standards.
Result
Enter a value and click "Convert" to see the result
Why Does 1 TB Show as 931 GB in Windows?
This is one of the most common storage questions — and the answer is that no storage is actually missing. Two different standards are being used to measure the same drive.
| Drive Label | Actual bytes | Windows shows | macOS shows |
|---|---|---|---|
| 500 GB | 500,000,000,000 | ~465 GB | ~500 GB |
| 1 TB | 1,000,000,000,000 | ~931 GB | ~1 TB |
| 2 TB | 2,000,000,000,000 | ~1,862 GB | ~2 TB |
| 4 TB | 4,000,000,000,000 | ~3,725 GB | ~4 TB |
Windows uses binary (1 TB = 1,024 GB). macOS (since 2009) uses decimal (1 TB = 1,000 GB), matching the manufacturer. The drive contains exactly the bytes advertised — Windows just measures them differently.
Frequently Asked Questions
Why does a 1 TB hard drive only show 931 GB in Windows?
Hard drive manufacturers define 1 TB as exactly 1,000,000,000,000 bytes (decimal standard). Windows measures in binary: 1 TB = 1,099,511,627,776 bytes. When Windows sees a 1,000 GB drive, it calculates 1,000,000,000,000 ÷ 1,099,511,627,776 ≈ 0.909 TB, which it displays as ~931 GB. No storage is missing — it's just two different measuring standards.
How many GB are in 1 TB?
Decimal (SI) standard — used by drive manufacturers: 1 TB = 1,000 GB. Binary (IEC) standard — used by Windows, macOS, Linux: 1 TB = 1,024 GB (tebibyte). This is the core reason for the apparent 'missing' storage on every hard drive and SSD.
How do I convert GB to TB?
Binary (operating systems): TB = GB ÷ 1,024. Decimal (storage manufacturers): TB = GB ÷ 1,000. Example: 2,000 GB ÷ 1,000 = 2 TB (decimal label on the box), but your OS will show 2,000 ÷ 1,024 = 1.953 TB.
How many GB is a 2 TB drive in Windows?
A 2 TB drive (2,000 GB decimal) will show as approximately 1,862 GB in Windows because Windows divides by 1,024 at each level: 2,000,000,000,000 bytes ÷ 1,024³ = 1,862.65 GB.
Does macOS use the same TB calculation as Windows?
No. Since macOS 10.6 (Snow Leopard, 2009), macOS switched to the decimal standard and reports storage in true SI gigabytes and terabytes (1 GB = 1,000,000,000 bytes). This means a 1 TB drive shows as approximately 1 TB in macOS but ~931 GB in Windows.