When you’re shopping for a new hard drive or choosing a cloud storage plan, one question often comes up: how many gigabytes are in a terabyte? The answer may seem simple at first, but it actually depends on how the storage is measured. There are two systems used in the tech world — decimal and binary — and they don’t always give the same result.
Understanding the difference between these systems will help you make better choices when buying or managing digital storage. Whether you’re backing up files, downloading games, or organizing media libraries, knowing how storage units work matters.
What Is a Terabyte and a Gigabyte?
A gigabyte (GB) and a terabyte (TB) are units of digital data. They represent how much information a device can store or transfer. One gigabyte is about the size of a full-length movie or 250 high-quality songs.
In simple terms:
- 1 gigabyte = 1,000 megabytes (in decimal)
- 1 terabyte = 1,000 gigabytes (in decimal)
These are commonly used to describe everything from USB drives to large cloud plans. But there’s more to it.
Quick Answer: How Many GB in a TB?
There are two answers — both correct, depending on the context.
- Decimal system (used by manufacturers):
1 TB = 1,000 GB - Binary system (used by computers):
1 TB = 1,024 GB
| Unit Type | Decimal (Base-10) | Binary (Base-2) |
|---|---|---|
| 1 Kilobyte | 1,000 bytes | 1,024 bytes |
| 1 Megabyte | 1,000 KB | 1,024 KB |
| 1 Gigabyte | 1,000 MB | 1,024 MB |
| 1 Terabyte | 1,000 GB | 1,024 GB |
Why Are There Two Different Numbers?
The reason lies in how systems count.
- Manufacturers use the decimal system (base 10), where each unit is 1,000 of the previous one. This makes their drives look bigger on paper.
- Operating systems use the binary system (base 2), where each unit is 1,024 of the previous one.
This difference means that when you plug in a 1 TB hard drive, your computer reports around 931 GB. That doesn’t mean the drive is faulty — it’s just a difference in counting.
Why Does My 1 TB Drive Only Show 931 GB?
This is one of the most common storage questions. Here’s why:
- The drive was measured using decimal (1 TB = 1,000 GB)
- Your operating system measures using binary (1 TB = 1,024 GB)
- 1,000 ÷ 1.024 ≈ 931 usable GB reported
Also, part of the drive is reserved for system files and file system structure (like formatting). That takes up some space too.
Real-World Examples of TB and GB
Understanding how much data fits into a terabyte can help you make smarter storage decisions.
- 1 TB SSD: Appears as ~931 GB on Windows
- 4K video: About 2–4 GB per hour. So 1 TB holds ~250 hours
- Photos: Around 250,000 high-quality images
- Cloud plans: Google One and Dropbox both offer 1 TB+ plans
- Gaming: Some AAA games exceed 100 GB; a 1 TB drive fits ~10 games of that size
How to Know What You’re Really Getting
When buying storage, keep this in mind:
- Check for terms like “formatted capacity” in product specs
- Expect your OS to show less than the advertised capacity
- Focus on usable space that fits your specific needs
For example, if you edit videos or use high-resolution media, a 1 TB drive might fill up quickly.
Optional: Binary Prefixes (GiB vs GB)
To reduce confusion, some experts suggest using binary prefixes:
- GiB (Gibibyte) = 1,024 MB
- TiB (Tebibyte) = 1,024 GiB
But most consumer products still use the more familiar decimal terms (GB, TB).
| Prefix | Binary Value | Decimal Equivalent |
|---|---|---|
| 1 GiB | 1,073,741,824 B | ~1.07 GB |
| 1 TiB | 1,099,511,627,776 B | ~1.10 TB |
Conclusion
So, how many gigabytes are in a terabyte? The answer is either 1,000 or 1,024 — depending on whether you’re using a marketing label or a computer’s internal reading.
The difference comes from how data is counted, not from missing space or errors. When you’re buying drives or choosing cloud storage, always consider what matters most: the usable space and your actual storage needs.
Got more questions about storage sizes? Drop them in the comments and share this with someone who’s buying a new drive!