How to Check SSD Size in Windows 10

Bought a 500 GB SSD and Windows says about 466 GB? Nothing is missing: the box counts in decimal gigabytes and Windows counts in binary ones. To see the real size and confirm the drive is an SSD, open Task Manager, select the Performance tab and pick the disk; it shows the type and capacity. For each drive letter’s size and free space, open This PC in File Explorer.

Which tool shows what

Windows 10 shows drive size in several places, and each answers a slightly different question. Pick the one that matches yours:

Tool	Total size of the physical SSD	SSD or HDD	Model name	Partitions and unused space	Exact bytes
Task Manager > Performance	Yes	Yes	Yes	No	No
This PC (File Explorer)	No, per drive letter only	No	No	No	Yes, in drive Properties
Disk Management	Yes	No	No	Yes	No
PowerShell (Get-PhysicalDisk)	Yes	Yes	Yes	No	Yes
System Information (msinfo32)	Yes	No	Yes	Partition count	Yes
Optimize Drives	No	Yes	No	No	No

If what you really want is free space rather than total size, the steps to check disk space on Windows 10 go deeper on that.

Why 500 GB shows up as about 466 GB

Drive makers define 1 GB as 1,000,000,000 bytes. Windows divides by 1,073,741,824 (1,024 cubed) but still prints “GB”, so every drive looks about 7% smaller than the label.

Size on the box	Bytes	What Windows shows (whole disk)
256 GB	256,000,000,000	about 238 GB
500 GB	500,000,000,000	about 466 GB
512 GB	512,000,000,000	about 477 GB
1 TB	1,000,000,000,000	about 931 GB
2 TB	2,000,000,000,000	about 1.82 TB

Those are whole-disk figures. Your C: drive will be smaller again, because Windows setup also creates a small EFI system partition and a recovery partition on the same SSD. Together they usually take well under 1 GB, though PC makers sometimes add a larger recovery partition of their own.

Quick check: take the advertised number in GB and multiply by 0.931. If Windows shows roughly that, the drive is the size it claims to be.

The fastest check: Task Manager

1. Right-click the taskbar and choose Task Manager (or use Ctrl + Shift + Esc). If you only see a small window, select More details.
2. Select the Performance tab.
3. Select a disk in the left column, for example Disk 0 (C:). The left column shows SSD or HDD under the name on current versions of Windows 10.
4. Read the model name at the top right, and Capacity and Type in the details under the graph.

Capacity is the whole physical disk. Formatted is how much of it belongs to partitions, which is why it can be smaller. If you have two drives, each one gets its own Disk entry; a USB SSD appears here too while it is connected.

This PC: size and free space for each drive letter

1. Press Windows + E to open File Explorer.
2. Select This PC in the left pane.
3. Under Devices and drives, each drive shows a bar and a line such as “182 GB free of 465 GB”.
4. For exact numbers, right-click the drive and choose Properties. The General tab lists Used space, Free space and Capacity in both bytes and GB.

This view counts each partition separately. A single 1 TB SSD split into C: and D: shows up as two smaller drives here, and the hidden EFI and recovery partitions do not appear at all. For a wider look at what is filling a drive, see how to check storage on Windows 10.

Find hidden partitions and unused space

1. Right-click Start and choose Disk Management.
2. In the lower half, each row is one physical disk. The label on the left shows the disk number, Basic, and the total size, for example Disk 0 Basic 465.75 GB Online.
3. The blocks to the right are the partitions: typically a small EFI System Partition, the large (C:) partition and a Recovery Partition.

Disk Management is the place to spot Unallocated space (a block with a black bar) that no partition uses. It does not say whether the disk is an SSD, so use it alongside Task Manager.

PowerShell and System Information: exact bytes and model

PowerShell

Right-click Start, choose Windows PowerShell and run:

Get-PhysicalDisk | Select-Object FriendlyName, MediaType, BusType, Size

You get one line per physical drive. MediaType reads SSD, HDD or Unspecified, and Size is in bytes. Microsoft’s MSFT_PhysicalDisk reference documents both properties. BusType shows how the drive connects, such as NVMe, SATA, USB or RAID.

To show the size in the same units as Windows and as the box, run:

Get-PhysicalDisk | Select-Object FriendlyName, @{n='Windows GB';e={[math]::Round($_.Size/1GB,1)}}, @{n='Box GB';e={[math]::Round($_.Size/1e9)}}

In PowerShell, 1GB means 1,073,741,824 bytes, so the first column matches Task Manager and the second matches the label. Unspecified in the MediaType column usually means the drive sits behind a RAID or USB controller that does not pass the type through, not that something is wrong.

System Information

1. Press Windows + R, type msinfo32 and press Enter.
2. Expand Components > Storage and select Disks.
3. Each drive lists its Model, Size (in GB with the exact byte count in parentheses) and number of partitions.

Older guides use the wmic diskdrive command for this. Microsoft has deprecated WMIC, so PowerShell is the better habit.

Is it really an SSD?

• Optimize Drives: search Start for Defragment and Optimize Drives. The Media type column says Solid state drive or Hard disk drive for each drive letter.
• Settings: Settings > System > Storage shows used and free space for the system drive. On recent Windows 10 versions, look for Manage Disks and Volumes under More storage settings to see each disk, its type and capacity; the exact label can vary by build (Microsoft’s storage settings page calls it Disks & volumes, the Windows 11 name).

Device Manager (under Disk drives) only shows model names, but that is enough to look up the official capacity on the maker’s website.

When the size looks wrong or the drive is missing

What you see	What it usually means	What to do
C: is much smaller than the disk, and Disk Management shows an Unallocated block	Part of the SSD is not in any partition, common after cloning to a bigger drive	Extend the partition into the free space; see how to resize a partition in Windows 10
A new SSD is in Task Manager or Disk Management but not in This PC	The disk has not been initialized or has no volume yet	Initialize it and create a volume; the steps to initialize an SSD work the same in Windows 10
The SSD is not in Disk Management at all	Loose connection, unsupported slot, or the drive is disabled in firmware	Recheck the cable or M.2 seating, and check that the drive shows in the PC’s firmware setup
Task Manager shows “SSD (RAID)” or only one disk for two drives	The storage controller is in RAID or Intel RST mode and presents the drives through it	Normal on many laptops; use the maker’s storage utility for per-drive details
The size is far larger or smaller than the 0.931 rule predicts	Wrong drive selected, a partition view, or a counterfeit drive	Compare Get-PhysicalDisk with the model’s official spec

A word on counterfeit drives, mostly cheap USB sticks and portable SSDs from marketplace sellers: Windows can only show the size the drive reports, and a fake drive reports more than it can store. The only real test writes data to the whole drive and reads it back, which can overwrite what is there, so copy your files off first and use a reputable capacity-test tool.

A note on support: Windows 10 reached end of support on October 14, 2025, and Microsoft says PCs enrolled in consumer Extended Security Updates stay protected until October 12, 2027 (Microsoft’s end of support notice). It does not change any of these tools.

Size checks before you clone or upgrade

Capacity matters most when you are about to copy Windows to a new drive. Compare used space, not total size:

1. In This PC, note Used space on C: (Properties shows it exactly). Say it reads 380 GB on an old 1 TB drive.
2. Work out what the new SSD will show in Windows with the 0.931 rule. A 500 GB SSD gives about 466 GB, minus well under 1 GB for the EFI and recovery partitions.
3. Leave headroom. In this example 380 GB fits into about 465 GB, but leaves little room for updates and new files, so a 1 TB SSD (about 931 GB) would be the more comfortable choice.

After the copy, check Disk Management on the new drive. If C: stops short and an Unallocated block sits beside it, extend the partition so you can use the full SSD.

Planning a bigger upgrade? Start by listing your computer specs in Windows 10 so you know which parts are worth replacing.

SSD size questions

How do I turn the byte count into the size on the box?

Divide by 1,000,000,000. For example, 512,110,190,592 bytes is about 512 GB on the box. Divide by 1,073,741,824 instead to get the figure Windows prints, about 477 GB.

Does an external USB SSD show its size the same way?

Yes. It gets its own Disk entry in Task Manager and Disk Management and its own drive letter in This PC, with the same decimal versus binary gap. Some USB enclosures hide the SSD type, so Get-PhysicalDisk may show Unspecified.

If the numbers check out but the drive is simply too small for what you keep on it, start by seeing what is using the space, then decide between cleaning up and moving to a larger SSD.