# Immich Storage Calculator: Size SSD, HDD, RAID and Backup Capacity A useful Immich storage estimate must account for more than the current photo folder. The primary pool needs room for future originals, generated media and free-space reserve. Redundancy then changes raw disk requirements, while independent backups add a separate copy budget. This calculator keeps those layers visible so a mirror or parity array is not accidentally counted as the backup. ## Buying answer Enter your current library, annual growth and planning horizon, then add a generated-media allowance, free-space reserve, primary redundancy and independent backup copies. The result separates projected originals, usable primary capacity, approximate raw primary capacity and backup capacity so you can price each layer with the live SSD, HDD and NAS listings above. ## Buying guide ### Start with originals, because they drive the scale The current library is the anchor for every other number. Measure the actual source photos and videos rather than the size of a backup archive that may include snapshots or duplicates. Then add expected annual growth for the number of years you want the new storage purchase to last. This produces the projected original-media footprint, which is the first capacity layer and the one that cannot be recreated from thumbnails or database metadata. ### Annual growth changes the correct drive class A 4TB household adding 200GB per year and a 4TB household adding 2TB per year should not buy the same pool simply because their current libraries match. Growth rate determines when bays fill, when parity overhead becomes painful and when a second chassis might be needed. Use a conservative but believable number from recent photo and video behavior, then rerun the model if phone cameras or family usage changes. ### Generated media belongs in the calculation Thumbnails and transcoded derivatives consume capacity beyond originals. Rather than imposing one universal ratio, the calculator exposes a generated-media percentage that you can tune. Start with a planning allowance, monitor real usage after Immich processes the collection, and replace the assumption with measured data. This keeps the calculator useful for both photo-heavy and video-heavy libraries without pretending their working-data footprint is identical. ### Free-space reserve prevents a paper-perfect design A pool that reaches its target only when almost full is not comfortably sized. Free space supports imports, maintenance, filesystem behavior and unexpected growth. The calculator increases the usable target based on an adjustable reserve so the storage plan has breathing room. This is different from redundancy: reserve protects operating headroom, while redundancy changes how raw drives are arranged to tolerate certain failures. ### Redundancy consumes raw capacity Mirror, single-parity and dual-parity approaches all turn raw disk capacity into a smaller usable pool. The calculator uses planning multipliers because the exact result depends on bay count, filesystem and platform. Treat the raw target as a shopping estimate, then use the NAS sizing page or your storage platform’s own calculator for the final layout. Never order drives from a generic multiplier without checking the actual array rules. ### Backups are counted separately on purpose An independent backup is not another label for the redundancy inside the primary pool. It should survive failures or mistakes that can affect the live array. That is why the calculator adds backup capacity after the primary raw estimate rather than folding it into RAID math. If you plan one local backup and one offsite copy, enter two independent copies and budget the storage destinations separately from the server’s data disks. ### SSD capacity and HDD capacity solve different jobs The total result does not mean every terabyte should be purchased in the same medium. Application/database storage can remain on a smaller local SSD while original media and backup copies live on economical hard drives or NAS systems. Use SSDs for the application tier and HDD or NAS storage for bulk originals and backups so the result becomes a practical tiered build instead of an unnecessarily expensive all-flash archive. ### Bay count is part of capacity planning Raw terabytes alone do not reveal whether the server can reach the target efficiently. A two-bay NAS may require very large drives to deliver the same protected usable capacity that a four- or six-bay system reaches with smaller disks. More bays also create different upgrade paths and power costs. Use the storage result to decide the capacity class, then model bay count before choosing the enclosure. ### Snapshots consume their own reserve If the storage platform keeps snapshots, versioned backups or other historical copies, those can use space beyond the live Immich dataset. This calculator’s reserve is intentionally broad rather than pretending to predict every snapshot policy. If your NAS retains substantial history, increase the reserve or budget snapshots explicitly with the platform’s monitoring data. A storage estimate should reflect the policy you actually intend to keep. ### Decimal drive capacity and displayed capacity differ Drive manufacturers sell decimal terabytes, while operating systems and storage tools may display capacity using different units or subtract filesystem and array overhead. Do not treat a slightly smaller displayed number as evidence that capacity is missing. The calculator works as a planning model in TB, and the final usable number should always be confirmed in the target NAS or filesystem before the pool is populated with important data. ### Price the next expansion, not only day one A good design has an affordable next step. If the initial array uses every bay, future growth may require replacing existing drives or adding another enclosure. If it leaves bays empty, the initial chassis may cost more but simplify expansion. Run the calculator with both the current horizon and a longer scenario. The difference reveals whether a smaller system is genuinely economical or merely defers a predictable upgrade. ### Recalculate after the real server is running Planning becomes more accurate after Immich has processed a representative library. Record original size, generated-data size, annual growth and actual free-space behavior. Update the calculator with those numbers and compare them to the assumptions used during purchase. Planning becomes more accurate when you measure the deployed system over time instead of treating the first estimate as permanent. Recalculate whenever the library or protection policy changes. ## Live Amazon prices See the canonical page for current or last-valid marketplace evidence.