Home NAS or cloud: which costs less

Photos, videos, documents and backups grow every year, and sooner or later the space on your phone and computer runs out. There are two routes: pay for a cloud subscription, billed every month by the terabyte, or buy a NAS, a small network server with its own drives, paid up front and then running on electricity.

This calculator compares the total cost of the two options over the horizon you choose, taking into account data growth, redundant copies on the NAS, drive replacement and power consumption. It works in any currency.

How the calculation works

• Cloud: each month you pay the price per TB on the data stored at that time, which grows steadily.
• NAS drives: enough capacity for the data at the end of the horizon, multiplied by the number of copies; drives are bought again every 5 years.
• NAS electricity: average power in watts × 730 hours a month × energy price.
• Break-even: the first month in which cumulative cloud spending reaches that of the NAS.

The verdict is based on the ratio between the NAS cost and the cloud cost, which does not depend on the currency.

How much the amount of data matters

The table uses fixed data for 5 years, cloud at 6 per TB per month, a 400 NAS, drives at 18 per TB with two copies, 25 W of power and energy at 0.30.

The key point is that a NAS has a high fixed cost and a low cost per TB, while the cloud only has a cost per TB. In this example the cloud wins below 2 TB, the NAS from about 4 TB upwards, and the advantage grows quickly with the data.

How much electricity matters

A NAS that is on all day always draws power. At 25 W and energy at 0.30 that is about 66 a year, or about 330 over 5 years: in the 1 TB example it is almost half of the NAS cost. A low-power model, drives that spin down when idle or switching off overnight reduce this item.

How much the cloud price matters

With a fixed 4 TB for 5 years and the same NAS, here is how the comparison changes with the cloud price:

Consumer plans with a lot of included space, or very cheap cold-storage services, can move break-even by years: use the price per TB you would really pay.

The four bands of the verdict

• NAS below 50% of the cloud: the NAS clearly wins.
• 50% to 85%: the NAS costs less, but weigh it against management time and an off-site backup.
• 85% to 115%: similar costs; convenience, security and remote access decide.
• Above 115%: the cloud costs less.

A NAS is not a complete backup

Copies on several drives protect against a drive failure, but not against theft, fire, accidental deletion or ransomware. The 3-2-1 rule recommends three copies of your data, on two different media, with one off site. Many people combine both: the NAS for the main archive and a cheap cloud for a backup copy of the most important data. In that case, add the backup cloud cost to the NAS side.

Limits of the calculator

The model buys the drives for the end-of-horizon data up front, assumes they last 5 years and that the NAS lasts the whole period. It does not include the value of setup and maintenance time, UPS units, routers or cloud data egress costs. Drive prices tend to fall over time, so buying gradually could cost less.

Frequently asked questions

Is a NAS or the cloud cheaper?

It depends mostly on the amount of data. With cloud at 6 per TB per month, a 400 NAS and drives at 18 per TB with two copies, over 5 years the cloud wins below 2 TB and the NAS from about 4 TB upwards.

How long does a NAS take to pay for itself?

With 4 TB and cloud at 6 per TB per month, about 30 months; with 8 TB about 17 months. With little data it may never pay for itself.

How much power does a NAS use?

A two-drive home NAS typically draws a few tens of watts on average. At 25 W and energy at 0.30 that is about 66 a year.

Why do copies need to be counted?

To protect against a drive failure, data is duplicated on two or more drives: with two copies you need twice the terabytes.

How long do NAS drives last?

Often several years, but the calculator assumes replacement every 5 years to be cautious.

Does a NAS replace a backup?

No. Internal copies protect against a drive failure, not against theft, fire or ransomware: you also need an off-site copy.

Does the cloud have hidden costs?

Some services charge for downloading data or for operations. If you expect them, include them in the price per TB per month.

How do I account for data growth?

Enter how many terabytes you add on average each year: the cloud bills them month by month, while the NAS needs enough space from the start.

Does the calculator include management time?

No, only costs. Setting up, updating and monitoring a NAS takes time, which should be weighed separately.

Is it worth combining a NAS and the cloud?

Often yes: the NAS for the main archive and a cheap cloud for a backup copy of the most important data.

Can I use it for a business?

Yes, for a basic estimate. For business use add support costs, UPS units and security requirements.

Does it work in any currency?

Yes. Enter all prices in the same currency; the verdict is based on the ratio between costs, which does not depend on the currency.