# What does a NAS cost per usable TB?

Choose how many drives and which RAID level. We rank every drive by what each usable terabyte costs.

 Cheapest per usable TB

 Usable space

 Cost of the drives

 Drives
 Layout
 Drive type
 Smallest drive (TB)

## Every drive, ranked

## How it works

Usable space is the drive size times the drives that hold data: all of them for single drives, one for a mirror, the count minus 1, 2 or 3 for RAID 5/6 and RAIDZ1/2/3, and half for RAID 10. Cost is the drive count times the lowest current eBay price for that model and size, so the cheapest drives may be used or refurbished: check the condition before you buy. Sizes are in decimal TB as drives are sold; your NAS shows about 9% less in TiB, plus filesystem overhead.

Pricing the rest of the box? The [home server builder](https://sharpest.ai/tools/build/home-server) fills every slot, and [all drives](https://sharpest.ai/storage) are ranked by $/TB.

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As of 2026-11-07. Canonical page: https://sharpest.ai/tools/nas-cost