RAID Calculator

How to Use This RAID Calculator

Use this RAID calculator to estimate how much storage space you can actually use in a RAID setup. Choose your RAID type, enter the number of drives, and add the size of each drive. The calculator will show your total space, usable space, protection overhead, and fault tolerance.

Step 1. Choose Your RAID Type

Select the RAID setup you want to check, such as RAID 0, RAID 1, RAID 5, RAID 6, RAID 10, RAID 50, RAID 60, or JBOD. Different RAID types offer different balances of speed, redundancy, and usable storage space.

Step 2. Enter the Number of Drives

Type in how many disks are included in the array. This affects both your total available space and the level of protection your RAID can provide.

Step 3. Enter the Size of Each Drive

Enter the size of one drive in terabytes. If all drives are the same size, you only need to enter it once. You can also use the quick size buttons for common drive sizes.

Step 4. Review the Result

Once the setup is valid, the calculator shows your estimated RAID capacity right away. If there is a configuration issue or an important limitation, you will also see a message explaining what needs attention.

Try our Geek RAID calculator for detailed storage planning

Need deeper control? Switch to the Geek RAID calculator for advanced options, detailed overhead insights, and full fault‑tolerance breakdowns.

What the Results Mean

Total drive space

This is the full raw capacity of all drives combined before RAID protection is taken into account.

Usable space

This is the estimated storage space you can actually use for your files after mirroring, parity, or other protection is reserved.

Space used for protection

This is the part of your storage that is used for redundancy, parity, or spare capacity rather than for your own data.

Efficiency

This shows how much of your total drive space remains available for storage after RAID overhead is applied.

Fault tolerance

This tells you how many drive failures a RAID setup may survive before data loss becomes likely. The exact result depends on the RAID type and layout.

RAID Types Explained

JBOD

Minimum drives: 1. Best when you want to use all available space and do not need redundancy. The drawback is simple: if the drive fails, your data is at risk.

RAID 0

Minimum drives: 2. Best for speed and full capacity. It offers no fault tolerance, so a single failed drive can make the array unavailable.

RAID 1

Minimum drives: 2. Best for simple mirroring and straightforward protection. The main trade-off is that only about half of the total drive space is usable.

RAID 5

Minimum drives: 3. Best for balancing usable space and protection. It can survive one drive failure, but parity overhead reduces available capacity.

RAID 6

Minimum drives: 4. Best for larger arrays where stronger protection matters. It reserves more space for redundancy than RAID 5.

RAID 10

Minimum drives: 4. Best for strong performance with redundancy. The trade-off is higher storage overhead because mirroring uses a large part of total capacity.

RAID 50

Minimum drives: 6. Best for larger grouped arrays that need a balance of speed, capacity, and protection. It requires correct group sizing to work as expected.

RAID 60

Minimum drives: 8. Best for grouped arrays where higher fault tolerance is more important than maximum capacity. It has more overhead than RAID 50.

Common Examples

Example 1. 4 x 2 TB in RAID 5

Total drive space is 8 TB. Usable space is about 6 TB because the equivalent of one drive is used for parity.

Example 2. 4 x 4 TB in RAID 6

Total drive space is 16 TB. Usable space is about 8 TB because two-drive parity is reserved for protection.

Example 3. 6 x 8 TB in RAID 10

Total drive space is 48 TB. Usable space is about 24 TB because half of the total capacity is used for mirrored protection.

Example 4. 8 x 2 TB in RAID 60

Total drive space is 16 TB. Usable space depends on the group size, but dual-parity overhead will significantly reduce available space.

Example 5. 1 x 4 TB in JBOD

Total drive space and usable space are the same at 4 TB, but there is no redundancy.

Which RAID Level Should You Choose?

Choose RAID 0 if speed matters most and you do not need fault tolerance.

Choose RAID 1 if you want a simple way to mirror data across drives.

Choose RAID 5 if you want a practical balance between usable space and protection.

Choose RAID 6 if you use a larger array and want better protection against multiple drive failures.

Choose RAID 10 if you want strong performance with redundancy and can accept higher overhead.

What This Calculator Does Not Show

• Actual usable size may vary slightly depending on formatting, controller behavior, and vendor implementation.
• This calculator estimates storage capacity. It does not predict whether data recovery will succeed after a failure.
• Some controller-specific RAID layouts may behave differently from the standard models used here.

FAQ

Need to Recover Data from a Failed RAID?

DiskInternals RAID Recovery can help you recover documents, photos, videos, databases, and other files from damaged or inaccessible RAID arrays.

• Supports RAID 0, RAID 1, RAID 5, RAID 6, RAID 10, RAID 50, RAID 60, and JBOD.
• Lets you preview recoverable files before purchase.
• Designed for step-by-step recovery from many common RAID failure scenarios.

Use the RAID RECOVERY FREE DOWNLOAD button above to get started. If you need help, you can also contact Technical Support.

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