What RAID Calculator helps you do

Compare raw and usable storage, capacity efficiency, minimum disk count and fault tolerance for common RAID levels. It shows how much usable space each level gives up for redundancy. The calculation uses the smallest disk size, so mixed-size arrays are limited by their smallest member.

Capacity math runs locally in your browser; no configuration is uploaded to Haivix.

How it works

Most tools here are offline calculators: the address math, RAID capacity, permission bits, TCP window sizing and transfer-time estimate all run in your browser with no request. The RDAP lookup is the exception, because registration data lives in public registries and the domain must be sent to a lookup service. Unit conventions matter throughout: a megabyte may mean 1,000,000 or 1,048,576 bytes, and a megabit is always one eighth of a megabyte. These are reference models, not live checks, so a port can be listed without a service running, a permission mode can be valid without being appropriate, and a RAID estimate can differ from formatted capacity.

How to use RAID Calculator

Choose a RAID level and enter the disk size and count.
Read the usable capacity, efficiency and fault tolerance.
Check the minimum disk requirement for the selected level.
Compare levels to see the trade-off between space and safety.

When to use it

Work out usable capacity before buying disks.
Compare RAID levels for a storage decision.
Check the minimum disk count for a chosen level.
Estimate how much parity overhead an array carries.
Explain why RAID 1 halves capacity.
Sanity-check a controller's reported usable size.

When not to use it

Do not treat usable capacity as formatted capacity; filesystems and controllers add overhead.
Do not use RAID as a backup strategy.
Do not use it for erasure coding or vendor-specific layouts.

Example

Four 4 TB disks in RAID 5 give 16 TB raw and 12 TB usable, or 75% efficiency, with tolerance for one disk. The same disks in RAID 6 give 8 TB usable, 50% efficiency and tolerance for two. RAID 10 requires an even count and gives 8 TB usable with at least one disk of tolerance.

What you can do with RAID Calculator

Compare RAID 0, 1, 5, 6 and 10.
Calculate raw and usable capacity.
Show capacity efficiency as a percentage.
Enforce minimum and even disk-count rules.
Report fault tolerance in disks.
Run the capacity math locally in the browser.

Example: check the model against the live system

Note the unit convention before comparing figures. Mbps and MB/s differ by a factor of eight, and MB and MiB differ by about 5 percent.

Treat a lookup as a starting point. A port reference, a permission mode and a RAID calculation all describe expectations, not the state of a running host.

Confirm on the system itself where it matters: ss or netstat for listeners, ls -l for permissions, the controller utility for array status.

Keep RAID in perspective. It protects against a disk failure, not against deletion, corruption, ransomware or a lost site.

Record the inputs alongside the result so a later comparison uses the same assumptions.

Check the time unit on latency. A round-trip time is usually milliseconds, and entering seconds changes the bandwidth-delay product by a factor of a thousand.

Treat registry data as a snapshot. RDAP records can be redacted, cached or updated after a transfer, so confirm ownership and expiry with the registrar.

What to know before you start

Usable capacity is raw capacity and will be lower after formatting and filesystem overhead.
RAID is not a backup and does not protect against deletion, corruption or disasters.
It does not model hot spares, rebuild time or controller-specific layouts.
Disk sizes are treated as decimal TB, not TiB.

Common mistakes

Assuming usable capacity equals the sum of the disks.
Using mismatched disk sizes and expecting the larger ones to contribute fully.
Confusing RAID 6 with RAID 5 tolerance.
Treating RAID as a substitute for backups.

Troubleshooting

If the disk count is rejected, the level requires a higher minimum.

If RAID 10 rejects an odd count, use an even number.

If the usable size is lower than expected, the array may include a hot spare.

If formatted capacity is lower still, filesystem and controller overhead explain the gap.

RAID Calculator