Estimate usable capacity and basic fault-tolerance notes from drive count, capacity per drive and RAID level.
Results are for information and preliminary estimation. For critical technical work, manufacturer data, local codes and qualified professional review take precedence.
Simple capacity: RAID0 = N×drive; RAID1 = one drive for a two-drive mirror; RAID5 = (N−1)×drive; RAID6 = (N−2)×drive; RAID10 ≈ N/2×drive. Real systems reserve metadata and may impose vendor rules.
Example: Four 8 TB drives in RAID5 provide about 24 TB raw usable capacity.
Computer and network tools provide practical capacity planning. Vendor limits, protocol overhead, codecs and real connection quality can move results away from theoretical values.
No. RAID improves availability but does not replace backups against deletion, ransomware, fire or controller failure.
Traditional RAID commonly uses the smallest drive as the capacity baseline; vendor-specific flexible arrays can differ.
Tell us if a calculation is unclear, incomplete or appears incorrect.