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NAS Storage Capacity Growth Planner

Find out how long your NAS storage will last based on your real data growth rate. Get a year-by-year projection, see when you'll need to upgrade, and find the cheapest expansion path.

This NAS storage capacity growth planner projects how long your current NAS will last based on total capacity, current usage, and your annual data growth rate. Outputs a year-by-year forecast showing when you'll hit capacity limits and compares drive expansion versus full NAS upgrade costs.

1 Your current data
Check your NAS dashboard or cloud storage usage. Estimate if unsure.
GB/year (auto-calculated from profile, edit to override)
2 NAS configuration
Not sure? RAID Calculator →
NAS performance degrades above 80–90%. We recommend acting at 80%.

Your Storage Timeline

Year-by-Year Projection

YearData% FullCapacityStatus

How Much Storage Do Different Users Actually Need?

User type Typical starting data Annual growth Suggested minimum (5-year)
Family photos + docs500 GB – 2 TB150–200 GB/yr4 TB usable (2-bay RAID 1)
Photo + video enthusiast2–5 TB500 GB – 1 TB/yr12 TB usable (4-bay RAID 5)
Media collector (movies, music)5–20 TB1–3 TB/yr24 TB+ usable (4–6 bay)
Small business (5–10 staff)1–5 TB200–500 GB/yr8 TB usable (4-bay RAID 5)
Surveillance (4 cameras, 24/7)0 TB (fresh)2–4 TB/yr16 TB+ usable (4+ bay)
Homelab (VMs, Docker, AI)1–3 TB500 GB – 1 TB/yr12 TB usable minimum

2-Bay vs 4-Bay — The Decision Most Beginners Get Wrong

The most common NAS buying mistake: choosing a 2-bay to save $200, then needing a full replacement within 2 years. Here's why a 4-bay is usually the smarter investment.

A 2-bay NAS running RAID 1 gives you exactly half your drive capacity as usable storage, two 8TB drives gives you 8TB usable. There's no way to add more drives. The only way to expand is to replace the entire NAS enclosure.

A 4-bay NAS running RAID 5 gives you 75% efficiency, four 8TB drives gives you 24TB usable. When you need more space, you replace one drive at a time with a larger drive. A 2-to-4-bay upgrade requires buying a new NAS; a 4-to-6-bay expansion requires a new enclosure but not new drives in most cases.

The maths: the price difference between a 2-bay and 4-bay entry-level NAS is typically $200–300 AUD. If you need to upgrade your 2-bay after 2 years, you're spending that same $200–300 again on a new unit, plus migrating your data. The 4-bay pays for its premium up front.

The exception: if your data genuinely won't grow beyond what a 2-bay can handle for 5+ years, and you value the smaller footprint, a 2-bay is a legitimate choice. This planner helps you check that assumption with real numbers.

AU pricing notes (March 2026): Drive upgrade prices are from Amazon AU, Scorptec, and Mwave current listings. NAS enclosure prices vary, check Scorptec and Umart for current AU retail. All usable capacity figures assume 1 TB = 1,000 GB (SI units), no filesystem overhead applied for simplicity.

Frequently Asked Questions

How do I know my annual data growth rate?
Check your cloud storage usage history (Google/iCloud show usage over time) or your NAS dashboard storage trends. If unsure, our defaults are based on typical usage patterns, family photo users grow about 150 GB/year, media collectors 500 GB–1 TB+/year.
Should I buy a 2-bay or 4-bay NAS?
For most users, 4-bay. A 2-bay with RAID 1 gives you only 50% of your drive capacity as usable storage and has no expansion path. A 4-bay with RAID 5 gives 75% capacity efficiency and lets you grow by adding drives. The upfront cost difference is $200–300 but saves you buying an entirely new unit in 2–3 years.
What happens when my NAS gets full?
Performance degrades above 80–90% capacity. Before that point, you can replace drives with larger ones (one at a time in RAID/SHR) or migrate to a larger NAS. Planning ahead with this tool helps you buy the right size from the start.
Does RAID type affect how much storage I get?
Significantly. The same 4 × 8 TB drives give you 32 TB (no RAID), 24 TB (RAID 5), 16 TB (RAID 6), or 16 TB (RAID 1 pair). Use our RAID Calculator to compare options.