RAID Storage Calculator - RAID 0/1/5/6/10 Capacity Calculator Free

How to Use the RAID Calculator

1. Select RAID level — choose from RAID 0, 1, 5, 6, or 10
2. Enter number of drives — the minimum varies by RAID type (e.g., RAID 5 needs at least 3 drives)
3. Enter drive capacity — input the capacity of each drive in TB or GB
4. View results — usable capacity, total raw capacity, fault tolerance, and storage efficiency percentage
5. Compare levels — switch between RAID levels to see how the numbers change with the same drives

Perfect for system administrators, CCTV installers, and IT professionals planning storage for NVRs and servers.

Features

• All common RAID levels — RAID 0 (striping), RAID 1 (mirroring), RAID 5 (striping with parity), RAID 6 (dual parity), and RAID 10 (mirror + stripe)
• Real-time calculation — results update instantly as you change inputs
• Fault tolerance — clearly shows how many drives can fail without data loss for each RAID level
• Storage efficiency — displays the percentage of raw capacity that is usable
• Performance notes — summarizes read/write characteristics and advantages of each RAID type
• Minimum drive validation — warns if the drive count is below the minimum for the selected RAID level

Use Cases

NVR storage planning — CCTV installers with a 16-channel NVR need to calculate how much video retention time different RAID configurations provide. The calculator helps compare RAID 5 (efficient, single-drive fault tolerance) vs RAID 6 (dual-drive fault tolerance for longer rebuild times) using the same set of drives.

Server deployment — system administrators planning a file server or database server calculate usable storage across multiple RAID levels. They compare RAID 10 for performance-critical databases against RAID 5 for bulk file storage using the same hardware budget.

Home media servers — enthusiasts building a NAS for Plex or home media use the calculator to decide between RAID 5 (better capacity efficiency) and RAID 1 (simpler, better redundancy) for a 4-bay system.

IT budgeting — when purchasing storage, the calculator helps determine how many drives are needed to achieve a target usable capacity with the desired level of redundancy.

FAQ

What is the difference between RAID levels?

RAID 0 splits data across drives for maximum speed but has no redundancy — one drive failure loses everything. RAID 1 mirrors data for full redundancy but uses 50% of raw capacity. RAID 5 uses one drive’s worth of parity for single-drive fault tolerance at ~80-90% efficiency. RAID 6 uses two parity drives for dual-drive fault tolerance. RAID 10 mirrors striped sets for both performance and redundancy.

Which RAID level is best for security camera NVRs?

RAID 5 is the most common choice for NVR storage. It provides single-drive fault tolerance (important for continuous recording) with good capacity efficiency. For larger arrays (8+ drives), RAID 6 offers extra protection since rebuild times are long and a second drive failure during rebuild is possible.

How many drives do I need for each RAID level?

RAID 0 needs at least 2 drives. RAID 1 needs exactly 2 drives. RAID 5 needs at least 3 drives. RAID 6 needs at least 4 drives. RAID 10 needs at least 4 drives (in pairs).

What happens if a drive fails in a RAID array?

In RAID levels with redundancy (1, 5, 6, 10), the array continues operating in a degraded state. The failed drive must be replaced and the array rebuilt from parity data. During rebuild, performance is reduced and the array is vulnerable to a second drive failure (except RAID 6).

What is “fault tolerance” in RAID?

Fault tolerance refers to how many drive failures the RAID array can survive without data loss. RAID 0 has 0 fault tolerance. RAID 1 and RAID 5 tolerate 1 drive failure. RAID 6 tolerates 2 drive failures. RAID 10 can tolerate multiple failures as long as no mirrored pair loses both drives.

Tips

• For RAID 5, consider using drives of the same capacity — the array is limited by the smallest drive
• RAID 6 is strongly recommended for arrays with 8+ drives due to the risk of URE (Unrecoverable Read Error) during rebuild
• Always maintain a spare drive (hot spare) to minimize the time the array operates in degraded mode after a failure