Storage and data resilience

Free interactive planner · Australia

NAS usable capacity and reserve planner

Estimate decimal usable drive capacity after reserving whole drives for a stated parity or mirror allowance.

A transparent estimate based on the values you enter. No account is needed.

Use the tool

Estimate decimal usable drive capacity after reserving whole drives for a stated parity or mirror allowance.

How the estimate works

Simplified usable capacity = (installed drives − drive-equivalents reserved) × capacity per drive. Decimal TB is used.

Explore eBay AU listing examples

These are dated API search matches, not a verified fit or recommendation. Checked: 30 Oct 2026 07:20 UTC. Listings may change or disappear.

eBay listing image for Synology RackStation RS812+ Network Attached Storage NAS No HDD 4x Caddy's

Synology RackStation RS812+ Network Attached Storage NAS No HDD 4x Caddy's

eBay AU search match checked 30 Oct 2026 07:20 UTC. Compare full model, condition, seller, shipping and return details.

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eBay listing image for New Western Digital WD40EFRX 4TB WD Red 3.5in SATA III NAS Storage Hard Drive

New Western Digital WD40EFRX 4TB WD Red 3.5in SATA III NAS Storage Hard Drive

eBay AU search match checked 30 Oct 2026 07:20 UTC. Compare full model, condition, seller, shipping and return details.

View this eBay matchCheck this item on AmazonAs an Amazon Associate I earn from qualifying purchases.
eBay listing image for QNAP TS-269 Pro 2-Bay NAS Network Attached Storage - 2x Trays - No PSU No HDD

QNAP TS-269 Pro 2-Bay NAS Network Attached Storage - 2x Trays - No PSU No HDD

eBay AU search match checked 30 Oct 2026 07:20 UTC. Compare full model, condition, seller, shipping and return details.

View this eBay matchCheck this item on AmazonAs an Amazon Associate I earn from qualifying purchases.

eBay Partner Network links may earn Vyonetix a commission. Verify exact product details with the seller and manufacturer.

About this tool

Plan a rough NAS capacity using the number of installed drives, capacity per drive, and the number of drive-equivalents reserved for redundancy. The result uses decimal terabytes and represents a simplified usable-capacity estimate. It does not model filesystem metadata, hot spares, RAID implementation differences, rebuild risk, snapshots, compression or backup copies. Redundancy is not a backup. Confirm the exact array level and vendor capacity calculator before selecting hardware, and keep an independent backup of data you cannot replace.

Frequently asked questions

Are these results guaranteed to fit?

No. Search matching and user-entered calculations do not establish compatibility. Verify part codes, dimensions and manufacturer guidance.

Are prices or stock shown?

No. Retailer pages show their current terms after you open them. This tool does not scrape or promise live prices or availability.

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