NAS & RAID Calculator

NAS planning example

RAID 1 vs RAID 5 Calculator

Compare usable TB, parity cost, and fault tolerance between RAID 1 and RAID 5 for NAS and homelab arrays.

Planning route

Answer the capacity question, then validate the purchase path

Use this worked example as a numeric starting point, then validate the RAID choice, capacity reserve, hardware plan, and backup path.

Editorial method

What this calculator can—and cannot—decide

The capacity model makes drive count, drive size, RAID layout, and reserve visible. It is a planning aid: it does not predict exact performance, rebuild duration, hardware compatibility, or the probability of data loss for a specific system.

Last reviewed: July 10, 2026. Product links remain neutral category searches until a partner relationship and page-level disclosure are in place.

Comparison Notes

This page compares RAID 1 and RAID 5 on identical hardware assumptions to help homelab builders choose between capacity efficiency and fault tolerance.

  • Disk size baseline: 8TB drives
  • Reserve policy: 10% filesystem headroom
  • Use the interactive tool for exact real-world constraints
Open Interactive Planner

Storage Capacity Table

Drives RAID 1 RAID 5 Delta
4x 8TB 7.20 TB 21.60 TB -14.40 TB
6x 8TB 7.20 TB 36.00 TB -28.80 TB
8x 8TB 7.20 TB 50.40 TB -43.20 TB
10x 8TB 7.20 TB 64.80 TB -57.60 TB
12x 8TB 7.20 TB 79.20 TB -72.00 TB

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FAQ

Does this comparison include filesystem reserve?

Yes. The comparison table applies a 10% reserve baseline to reflect realistic operating headroom in NAS and homelab environments.

Can two layouts with similar available space still have very different rebuild risk?

Yes. Similar usable TB does not imply similar failure tolerance or rebuild exposure. Capacity and resiliency should be evaluated together.

Which has more effective capacity: RAID 1 or RAID 5?

This NAS planning scenario compares both modes at fixed drive sizes so you can see usable capacity differences before buying disks.

Does RAID 1 rebuild faster than RAID 5?

Rebuild behavior depends on array width, disk size, and workload pressure. This page focuses on capacity and tolerance; benchmark your actual platform before final choice.