How Much NAS Storage Do I Need?
NAS storage needs vary wildly. A Plex library with 500 movies needs 10–15 TB. A photographer archiving RAW files might need 4–8 TB. A home backup server might need 2–4 TB per computer. This page helps you estimate your actual storage requirement and find the best-priced NAS drives to fill it.
Quick capacity estimates
1 TB holds roughly: 200,000 photos (5 MB each), 500 hours of 1080p video, 170 hours of 4K video, or 15,000 hours of FLAC music. For a Plex media server, plan 1.5–3 TB per 100 movies (mix of 1080p and 4K). For computer backups, plan 1.5x your current used space per device to allow for growth.
Quick Verdict
- Who this is for
- First-time NAS builders and anyone upgrading their NAS who wants to buy the right amount of storage without over- or under-spending.
- What usually wins
- Start with 2x your current data plus 50% headroom for growth. For a Plex server, that usually means 8–16 TB usable. For home backups, 4–8 TB usable. Buy NAS-rated CMR drives at the best price per TB.
- Prioritise
- Calculate your usable capacity after RAID overhead. Then find the cheapest NAS-rated drives per TB at your target capacity.
Prices updated hourly from Amazon US and UK. All links go directly to the retailer. Details.
Best Value NAS Drives
NAS-rated hard drives ranked by price per TB — the foundation of any NAS build.
High-Capacity NAS Drives (12 TB+)
The largest NAS drives for maximum storage density per bay.
Budget NAS Drives (4–8 TB)
Affordable entry-level NAS drives for 2-bay setups and first-time builders.
How to Choose
Sizing NAS storage requires thinking about both current needs and near-term growth.
RAID overhead
RAID 1 (mirror) uses 50% of raw capacity for redundancy. RAID 5 / RAIDZ1 loses one drive worth of capacity. RAID 6 / RAIDZ2 loses two drives. A 4-drive NAS with 16 TB drives gives 48 TB raw but only 32 TB usable in RAID 5.
Media libraries
A 1080p movie averages 5–15 GB. A 4K movie averages 30–80 GB. A large Plex library with 1,000+ titles easily exceeds 20 TB. Linux ISOs and other large collections scale similarly.
Growth rate
Most users add 1–3 TB per year to their NAS. Buy 50% more capacity than you need today — it is cheaper to buy slightly larger drives now than to rebuild the array later.
Number of bays
2-bay NAS suits small deployments (RAID 1 only). 4-bay is the mainstream sweet spot (RAID 5 or RAID 10). 6–8 bays for serious media collections or multi-user setups. More bays means more flexibility for future expansion.
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