How Many GB Is 1 TB? Exact Answer

1 TB equals 1,000 GB in the decimal system that drive manufacturers use.

In the binary system that Windows uses, 1 tebibyte (TiB) equals 1,024 gibibytes (GiB), so a new 1 terabyte drive displays as about 931 GB. Both numbers describe the same one trillion bytes.

Today, I'm going to show you the exact math behind the TB to GB conversion.

You'll also get a full data storage units breakdown, an advertised vs. displayed capacity guide, and a step by step walkthrough for checking your drive's actual usable storage.

How Many GB in 1 TB? The Quick Answer

Here's the deal: this question has two correct answers, and both are officially recognized. The first comes from the decimal system (base 10), where every step jumps by 1,000. The second comes from the binary system (base 2), where every step is 1,024. Most of the confusion you see online happens because people mix these two systems together. So let me lay out both answers clearly, including the reverse conversion that most guides skip.

In decimal terms, 1 TB equals 1,000 GB, or 1,000,000 MB, or exactly 1,000,000,000,000 bytes.

In binary terms, that same 1 TB equals 931.32 GiB, or about 953,674.32 MiB.

Going the other way, 1 TiB equals 1,024 GiB, which works out to 1,099.51 GB in decimal, or exactly 1,099,511,627,776 bytes.

Bottom line? When a product box says "TB," think 1,000 GB.

Data Storage Units: Byte to Exabyte

Before we go further, you need the full picture. Terabytes sit in the middle of a much bigger ladder of data storage units, and each rung follows the same pattern. In decimal, every unit is 1,000 times the one before it. In binary, every unit is 1,024 times bigger. The gap between the two systems widens with every step, which is exactly why terabyte drives look "smaller" than gigabyte drives ever did. These values come straight from the definitions published by NIST.

On the decimal side, a kilobyte (KB) is 1,000 bytes, a megabyte (MB) is 1,000,000 bytes, a gigabyte (GB) is 1,000,000,000 bytes, and a terabyte (TB) is one trillion bytes. Above that, a petabyte (PB) is 1,000 TB and an exabyte (EB) is 1,000 PB.

On the binary side, a kibibyte (KiB) is 1,024 bytes, a mebibyte (MiB) is 1,048,576 bytes, a gibibyte (GiB) is 1,073,741,824 bytes, and a tebibyte (TiB) is 1,099,511,627,776 bytes. The pebibyte (PiB) and exbibyte (EiB) follow the same 1,024 pattern.

Quick tip: bits vs. bytes matters too. One byte is 8 bits, so 1 TB holds 8 trillion bits.

Decimal vs. Binary: Why There Are Two Answers

Now, you might be wondering why the tech world can't just pick one number. Honestly, I get it. The short story is that early engineers noticed 1,024 was close to 1,000, so they borrowed the metric prefix "kilo" as a shortcut. That worked fine when files were tiny. However, as drives grew into terabytes, the gap between the two systems grew to about 9%. Eventually, standards bodies stepped in to clean up the mess.

The Decimal System (SI Prefixes)

The decimal system is the one you use every single day. A kilometer is 1,000 meters, and storage works exactly the same way under SI prefixes. One gigabyte is one billion bytes, and one terabyte is one trillion bytes. The IEC says these prefixes should keep their base 10 meaning in computing.

Apple follows this rule closely. Its product specs define 1 TB as one trillion bytes, and since Mac OS X 10.6 Snow Leopard, macOS calculates file sizes in decimal.

The Binary System (IEC Binary Prefixes)

Computers, on the other hand, think in powers of two. To end the confusion, the IEC introduced binary prefixes in 1999: kibi, mebi, gibi and tebi. So one gibibyte (GiB) equals 1,073,741,824 bytes, and one tebibyte (TiB) equals 1,099,511,627,776 bytes.

Simple enough, right?

The catch is that Windows still uses binary math but labels the result "GB" instead of "GiB." That single labeling choice causes most of the confusion you'll ever run into.

Where RAM Fits In

Here's a fun exception worth knowing. Memory modules still use the traditional binary labels, so a "16 GB" stick of RAM actually holds 16 GiB. That's because RAM is addressed in powers of two by design.

Keep this in mind, because RAM vs. storage measurement trips up plenty of buyers.

Storage uses decimal. RAM uses binary. Remember that, and you're ahead of most people.

Why Does My 1 TB Drive Show 931 GB?

This is the big one. You plug in a shiny new drive, open File Explorer, and see 931 GB instead of 1,000. Frustrating? Absolutely. But the math explains everything. Seagate confirms that manufacturers advertise capacity in decimal, while Windows divides by 1,024 at every step and still shows "GB." In other words, your drive holds exactly what the box promised.

Here's the math:

1,000,000,000,000 bytes ÷ 1,073,741,824 = 931.32 GiB

Seagate uses a great analogy. One kilometer and 0.621 miles describe the same distance. Different unit, same road.

On top of that, a small slice goes to file system overhead. Apple calls what remains the actual formatted capacity.

Fun fact: this confusion even went to court. In Safier v. Western Digital, the settlement required Western Digital to spell out its GB definition on future packaging. The suit claimed an 80 GB drive really held 74.4 GB.

Advertised vs. Displayed Capacity: 256 GB to 20 TB

I ran the numbers for the most popular drive sizes, so you never have to guess again. Below, you'll see what the box says next to what Windows will show you. Notice how the gap grows as drives get bigger: a 256 GB drive "loses" about 18 GB, while a 20 TB drive "loses" nearly 2 TB of displayed space. Every byte is still there, though. Use these figures to double check any new drive in seconds.

For smaller drives, a 256 GB drive shows as 238.42 GB, a 512 GB drive shows as 476.84 GB, and a 1 TB drive shows as 931.32 GB. That's a displayed gap of about 6.9%.

For bigger drives, a 2 TB drive shows as 1.82 TB, a 4 TB drive shows as 3.64 TB, and an 8 TB drive shows as 7.28 TB.

At the high end, a 12 TB drive shows as 10.91 TB, a 16 TB drive shows as 14.55 TB, and a 20 TB drive shows as 18.19 TB. That's a displayed gap of about 9.1%.

Why does the gap jump from 6.9% to 9.1%? Because Windows switches from showing GB to showing TB. At the TB level, it divides by 1,024 four times instead of three.

How to Convert TB to GB (Step by Step)

Want to do the conversion yourself? Good news: it takes about ten seconds and nothing beyond basic multiplication. I'll walk you through every direction you're likely to need, including GB to TB and TB to MB. First, decide which system you're working in. Then follow the steps below. Next time a spec sheet or a cloud plan looks suspicious, you'll know exactly what's going on.

Find the capacity in TB. Check the box or product page. Example: 2 TB.
For decimal GB, multiply by 1,000. So 2 × 1,000 = 2,000 GB.
For what Windows shows, multiply by 931.32. So 2 × 931.32 = 1,862.65 GB.
For GB to TB, divide by 1,000. So 500 GB ÷ 1,000 = 0.5 TB.
For TB to MB, multiply by 1,000,000. So 1 TB = 1,000,000 MB.
For TiB to GiB, multiply by 1,024. So 1 TiB = 1,024 GiB.

How to Check Your Drive's Real Capacity

Numbers on a box are one thing. Seeing the real byte count on your own screen is another. Luckily, both Windows and macOS show you the exact number of bytes if you know where to look. This is also a smart way to spot a fake or faulty drive, because a genuine 1 TB drive should report roughly one trillion bytes. Western Digital recommends the same byte count method.

On Windows:

Open File Explorer.
Right click your drive and choose Properties.
Look at Capacity. You'll see total bytes plus the binary "GB" figure.

On Mac:

Click Go > Utilities and open Disk Utility.
Select your drive.
Check the capacity. macOS counts in decimal, so a 1 TB drive shows close to 1 TB.

That's it. Easy.

How Is Cloud Storage Measured?

Here's something most guides completely ignore. Cloud storage plans are advertised in GB and TB too, but providers don't always count the same way. For example, Google Workspace Individual comes with 1 TB of storage, and consumer Google One plans go up to 5 TB. Meanwhile, Google Cloud Storage openly states that it bills in binary gigabytes. So the "TB" you pay for can mean different things depending on where you pay for it.

Case in point: Google Cloud's pricing page says it counts storage in JEDEC binary gigabytes, where 1 GB equals 2³⁰ bytes and 1 TB equals 1,024 GB.

My advice? Before you pick a cloud plan, check the provider's documentation for which system it uses. And if you're choosing hosting for heavier projects, our guide on how cloud servers compare with VPS and dedicated servers shows where the costs really add up.

How Much Can 1 TB Actually Hold?

Okay, so 1 TB equals 1,000 GB. But what does that mean in real life? Big numbers are hard to picture, so I did the math using typical file sizes. Your results will shift with your camera, video settings and compression, so treat these as solid ballpark figures. I've listed the file size I assumed for each example, so you can adjust the math for your own files.

Photos: At about 5 MB per JPEG, 1 TB holds roughly 200,000 photos. At about 25 MB per RAW file, that drops to around 40,000 photos.

Music: At about 4 MB per MP3 song, 1 TB fits roughly 250,000 songs.

Movies: At 4.7 GB per DVD quality movie, you can store about 212 movies.

Games: If your games average 100 GB each, 1 TB holds about 10 games. Large AAA titles near 150 GB each cut that to about 6 games.

Video: This storage capacity estimate puts 1 TB at roughly 1,280 minutes of 4K iPhone HEVC video, or over 7,900 minutes of 1080p H.264 footage.

Is 1 TB Enough? How to Pick the Right Drive

This is where things get practical. Storage is cheap compared to losing your files, and running out of space always seems to happen at the worst possible moment. So instead of guessing, match the drive to how you actually use your computer. I always recommend buying one size up from what you need today, because your photos, games and projects will only keep growing. Here's how I'd choose.

Students and everyday users: A 1TB SSD or 1TB external hard drive covers documents, photos and apps comfortably.
Gamers: Go for 2 TB, because a handful of modern games can fill 1 TB fast.
Photographers: Choose 2 TB or more if you shoot RAW.
Video creators: Start at 4 TB for 4K footage plus backups.

Here's my honest take: don't let the 931 GB number scare you off. A quality 1 TB drive from a trusted brand like Seagate or Western Digital delivers every single byte it promises.

One more thing. A bigger drive only helps if your files stay safe on it. If you store work or client data, read our guide to data loss prevention software to protect what you save. Then grab the drive that fits your budget and enjoy years of breathing room.

Frequently Asked Questions

Still have questions? You're not alone. Below, I've answered the questions people search for most about terabytes and gigabytes. Each answer is short and to the point, so you can find what you need fast. If your question isn't here, the conversion steps above will almost certainly cover it. Let's clear up the last bits of confusion once and for all.

Is 1 TB 1,000 GB or 1,024 GB?

1 TB is exactly 1,000 GB under the international SI standard, which drive makers, Apple and the IEC all use. The 1,024 figure belongs to the binary unit, the tebibyte (TiB), which equals 1,024 gibibytes (GiB). Many websites mix these up, but only the 1,000 GB answer matches what you see on a product box.

Why does my 1 TB SSD show 931 GB?

Your 1 TB SSD shows 931 GB because Windows measures storage in binary. It divides one trillion bytes by 1,073,741,824 and labels the result "GB" instead of "GiB." The drive still has every byte you paid for. Formatting and system files use a small extra slice, so your free space will be slightly lower still.

How many GB is 2 TB?

2 TB equals 2,000 GB in decimal terms, which is the number printed on the box. In Windows, the same drive shows about 1,862.65 GB, or 1.82 TB, because of binary counting. To convert any TB figure yourself, multiply by 1,000 for decimal GB, or by 931.32 for the number Windows displays.

How many MB are in 1 TB?

There are 1,000,000 MB in 1 TB under the decimal system. In binary, there are 1,048,576 MiB in 1 TiB. If you want to see how many binary MiB fit in a decimal 1 TB drive, the answer is about 953,674 MiB. Most file managers on Windows will show you this binary figure.

Is 1 TB enough for gaming?

1 TB works for casual gamers who keep a few titles installed at a time. However, many modern games take 100 GB or more each, so a 1 TB drive can fill up with around ten large games. If you play several big titles, a 2 TB drive is the smarter long term buy.

What is bigger than a terabyte?

A petabyte (PB) is the next unit up, equal to 1,000 TB or one quadrillion bytes. After that comes the exabyte (EB), equal to 1,000 PB. In binary, the matching units are the pebibyte (PiB) and exbibyte (EiB), each 1,024 times the previous unit. Most home users will never need anything beyond terabytes.

Does cloud storage use GB or GiB?

It varies by provider. Consumer plans like Google One are advertised in GB and TB, while Google Cloud Storage states that it bills in binary gigabytes, where 1 GB equals 2³⁰ bytes. Always check your provider's documentation, because the same "1 TB" label can mean slightly different amounts in different services.

The Final Word

So, how many GB is 1 TB? The answer is 1,000 GB on the box and about 931 GB in Windows, and both describe the exact same storage. Now you know why the numbers differ, how to convert them in every direction, how to check your own drive, and how much 1 TB really holds. With that knowledge, you can shop with total confidence and skip the buyer's remorse.

Go pick up the right drive for your needs today.

And stop worrying about those "missing" gigabytes for good.