UniFi UNAS File Storage Size Calculator

Choosing a UniFi UNAS is more than matching drives to your data. Previous versions, growth and drive protection all take space. This calculator adds them up, then recommends the UNAS, drives and RAID level to buy, plus the cloud space for a second, off-site copy.

UniFi UNAS storage calculator

Answer four questions. The recommended UNAS, drives, RAID level and cloud backup size update as you go.

How much data do you need to store?

Count everything that will live on the NAS today, from 100 GB to 100 TB.

Room to grow

Little or noneNo allowance SteadyAdds 25% FastAdds 50%

What kind of files are they?

Some files are saved over and over, others are added once and left alone.

Office documentsWord, Excel, PDFs, email archives Mixed business filesA bit of everything Photos and mediaMostly added, rarely edited Video productionLarge files, edited often Design and CADBig project files saved many times Backups and VMsImages that change every run

How often do your files change?

From an archive that’s barely touched to a busy office saving changes all day.

Most daysRegular day-to-day work.

How many previous versions should it keep?

Each version is a snapshot you can roll a file or folder back to. Choose from 2 to 100.

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Usable storage to plan for

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Your filesWhat you entered
Previous versions
Growth allowance
Kept free (20%)Storage pools slow down as they fill up
Spare capacityLeft over in the recommended setup

Your recommended UniFi setup

RAID level
Drives
Usable space
Protection

Second copy in the cloud

UniFi Drive can push a scheduled copy from the UNAS straight to a cloud provider, so a fire, theft or ransomware attack at the office can’t take every copy at once. Versions stay on the UNAS, so the cloud only needs the latest copy of each file.

Cloud space to plan for

Your files plus growth, with a 10% margin. No versions included.

These are planning estimates based on typical change rates, not a guarantee: real snapshot use depends on how your files are edited. Drive part numbers are UniFi’s own; NAS-rated drives of the same size work too. Check compatibility before buying.

How the UNAS storage calculator works

It builds up the space you need in layers, then finds the most cost-effective UniFi setup that holds it with room to spare.

Your files
The amount you store today, from 100 GB to 100 TB.
Previous versions
Each snapshot only stores what changed since the last one, so the space depends on your file type, how often files change and how many versions you keep.
Growth and free space
An allowance for growth, then 20% kept free, because storage pools slow down as they fill up.
Drive protection
RAID 1, 5, 6 or 10, chosen by drive size and workload, then the UNAS and drives that fit.

UniFi UNAS installation and support

We are specialist Ubiquiti UniFi installers, working across the full UniFi range. If you would rather not choose drives and RAID levels yourself, send us the figures from the calculator and we will confirm the right setup and install it for you.

On site across East and South London, Kent and East Sussex, and along the US East Coast from Florida to New York.
Remote support for customers worldwide.
A senior engineer, not a call centre. Contract customers deal directly with one, and even complex issues are typically resolved the same day.
Flexible contracts from 3 to 24 months, with many services also available on a rolling month-to-month contract.

See our UniFi services, or explore the rest of the range in the Ubiquiti Universe.

Common questions about UniFi UNAS storage

Why does a 24 TB drive show less space in UniFi Drive?

Drive makers count a terabyte as 1,000 gigabytes, while UniFi Drive reports space in binary units, so a 24 TB drive shows as roughly 21.8 TB. The file system also keeps a little space for itself. The calculator allows for both, so its usable figures are close to what UniFi Drive will show.

How much space do previous versions take up?

UniFi Drive snapshots are copy-on-write, so each version only stores the parts of files that changed since the one before. A quiet archive can keep 100 versions for very little extra space, while a busy office saving large files every day needs far more. That is why the calculator asks what kind of files you keep and how often they change.

Why does the calculator choose RAID 6 for large drives?

When a drive fails, the UNAS rebuilds its contents onto a replacement, and with 16 TB or 24 TB drives that can take many hours. RAID 5 cannot survive a second failure during that window; RAID 6 can. For drives of 8 TB or less, rebuilds are short enough that RAID 5 is a reasonable choice.

Can you install and set up a UniFi UNAS for us?

Yes. We are specialist Ubiquiti UniFi installers. We work on site across East and South London, Kent and East Sussex, and along the US East Coast from Florida to New York, and we support customers remotely worldwide. Contact us with your calculator results and we will confirm the right setup.

Want us to size and install it?

Send us your calculator results and we’ll confirm the UNAS, drives and backup plan.

Get in touch