RAID capacity planner

See the capacity trade-off before the shopping list.

Compare equal-size drive layouts with the protection overhead and planning reserve visible. Start here when your decision is array shape and usable capacity, then continue to the wider NAS plan for growth and recovery.

Capacity planner

Compare an equal-size array before you buy drives.

Set the array layout, drive count, decimal drive label, and operating reserve. The result keeps raw capacity, layout overhead, and planning headroom separate in TB and TiB.

View assumptions and sources →

The values below are editable planning baselines. Change the few inputs you know; open Advanced assumptions only when they change your decision.

Raw drive labels——
Layout capacity——
Planning capacity——
Fault tolerance——
Next decision

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Array brief

Save the capacity assumptions with the result.

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Next decision

Estimate the rebuild windowCompare all layoutsReturn to storage baseline

Plan tools

Keep this useful version close, shareable, and easy to revisit.

Reset inputs

Optional support

Keep practical planning tools available.

If this result made the next decision clearer, an optional contribution helps cover hosting, source reviews, and continued improvements.

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What it models

Equal-size drive capacity, mirror or parity overhead, valid layout rules, and an optional planning reserve.

What to verify

Filesystem overhead, mixed-drive behavior, supported expansion paths, drive compatibility, and backup retention for the platform you choose.