← NAS & RAID Calculator

NAS pSEO Landing

6x 18TB RAID 6 NAS Calculator | Usable TB

Estimate usable TB, parity overhead, and fault tolerance for 6x 18TB in RAID 6. Includes reserve planning for NAS and homelab arrays.

Capacity Snapshot

Raw Capacity

108.00 TB

Usable Capacity

64.80 TB

Fault Tolerance

2 drives

Efficiency

66.7%

Safer for larger arrays with dual parity, at the cost of one extra parity disk. This scenario applies a 10% filesystem reserve.

Run Interactive Calculator →

Alternative Mode Comparison

Mode Usable Tolerance Efficiency
RAID 5 81.00 TB 1 drive 83.3%
RAID 6 64.80 TB 2 drives 66.7%
RAID 10 48.60 TB 1 drive per mirror pair* 50.0%
RAID-Z1 81.00 TB 1 drive 83.3%
RAID-Z2 64.80 TB 2 drives 66.7%

NAS Cluster Guides

NAS Hub RAID Level Compare RAID Capacity Matrix Planning Quick Sheet RAID Selector NAS FAQ

Related Long-Tail Calculators

2x 4TB RAID 1 2x 6TB RAID 1 2x 8TB RAID 1 2x 10TB RAID 1 2x 12TB RAID 1 2x 14TB RAID 1 2x 16TB RAID 1 2x 18TB RAID 1 2x 20TB RAID 1 3x 4TB RAID 1 3x 4TB RAID 5 3x 4TB RAID-Z1 3x 6TB RAID 1 3x 6TB RAID 5 3x 6TB RAID-Z1 3x 8TB RAID 1

Sequential Long-Tail Navigation

← Previous: 6x 18TB RAID 5 NAS Calculator | Usable TB Next: 6x 18TB RAID 10 NAS Calculator | Usable TB →

FAQ

How much real-world usable storage does 6x 18TB RAID 6 provide?

This NAS planning scenario estimates 64.80 TB usable after a 10% reserve from 108.00 TB raw.

Can this calculator replace real-world benchmark and rebuild testing?

No. Use this page for pre-purchase sizing, then validate with workload benchmarks, SMART health policy, and a tested restore plan.

How many disk failures can RAID 6 tolerate in this setup?

This setup can tolerate 2 drives. Real-world survivability depends on mirror placement, rebuild stress, and drive health.

Should I optimize this 6-drive plan for available space or resiliency first?

For long-lived NAS pools, resiliency first is usually safer. Capacity can be expanded later, while a risky parity choice can force migration sooner.