Smart Utilities

RAID Recovery Calculator

Estimate RAID usable capacity, failed-drive tolerance, recovery complexity, and safest next steps before rebuilding, replacing drives, or scanning a NAS array.

Calculate RAID Recovery Risk

Enter the array layout and failure details. The calculator runs locally and does not connect to a server.

1. RAID layout

RAID level

Number of drives

Drive size

Size unit

Failed / missing drives

Current array status

Stripe size

Likely file system

Optional notes

Do not rebuild, initialize, or change drive order before you understand the risk.

2. Recovery risk factors

Drive order is unknown or changedWrong order can corrupt reconstruction and scans. Rebuild failed or was interruptedFailed rebuilds can overwrite parity or metadata. Multiple drives have errorsUnstable drives make RAID recovery more complex. Clicking, beeping, or disconnecting drivesPhysical failure requires imaging before logical recovery. NAS/controller was initialized or resetNew metadata may overwrite parts of the original layout. Business-critical or irreplaceable dataRisk tolerance should be lower when data value is high.

Ready to calculate

RAID result will appear here

Enter the array details to calculate usable capacity, fault tolerance, and recovery risk.

Estimated usable capacity —

Recovery risk —

Total raw size —

Fault tolerance —

Array condition —

DIY safety —

What this means

Your RAID layout explanation will appear here.

Recovery-safe next steps

Your safest next steps will appear here.

Important: Do not rebuild, initialize, format, or change disk order unless you have verified backups or a recovery plan.

Capacity estimate

Calculates raw and usable storage for common RAID levels using the smallest drive size assumption.

Recovery triage

Flags rebuilds, unknown drive order, multiple failures, and physical drive symptoms as high-risk conditions.

No API required

This tool is a single static HTML file with local JavaScript logic. It does not upload RAID details or connect to a backend.