I’m pretty interested in the technical and financial aspects of storage and backups, so I decided to do a calculation estimate of what the cost per GB is for a typical home user. Then that number can be compared with the price of backup providers, to see what sort of deal you are getting from a company that specialises in storage of data.

### Price of data at home

So I went to newegg.com to check out how much hard drives currently cost. I’m going to shoot from the hip and estimate that the average user doesn’t use more than 1TB of space, and I think that is overestimating it. So I will be making my calculations with a 1TB hard disk drive. Currently the average price of these is **$89.99**.

So, per GB you are paying around **9c**. But, it is difficult to compare this to online backup services, since most of them charge for time (months & years), as well as the space you need.

Now, looking at some statistics from Boston Computing, 6% of “computers” will suffer data loss in the next year. So, statistically that means my hard drive wil fail every **17 years**.

Now we have a “time” adjusted price per GB, 9c divided by 17, means **0.52c per GB per year**. That is the cost per GB of your data at home.

### Price of online backups data

Some providers offer unlimited space so it would be pretty difficult to calculate a price per GB. But, in the last calculation I assumed 1TB of data, so let’s assume the same here. Since I know how much providers charge, I can say that BackBlaze is one of the cheapest providers around, charging **$3.96** for unlimited space per month, if you *pay for 2 years upfront*.

Please excuse me for the fact that I won’t use finance formulas (discount values, present values), although there are such things as inflation (so **$89.99** for a hard drive now might be more expensive now than paying the same monthly for online backups due to inflation).

Anyway, back to reality. **$3.96** per month for 17 years is **$807.84**. Price per GB? **$0.80. **So dollar for dollar, or cent for cent, you are paying around 400x online storage prices.

### The Result

So, in a completely mathematical analytics where the only factor is price per GB, here are the results:

Home price: **$0.005**

Online Backup price:** $0.80**

### Does this mean online backups are a con?

This is an online backups comparison site, so obviously I’m not going to say yes. I’m biased. But, you have to consider the points I’m about to make. The **value **of online backups is **not** the price per GB, although that is important too. What else do they offer?

– Using a second hard disk to back up means the same **physical location**. What if you spill tea on your PC? What if there’s a fire? The 17 years statistic I used is only for natural hard disk failure, human error is common. Decent backups need more redundancy than a second hard disk in the same location. In fact, you might just accidentally delete a file. Online backups can be useful even if it isn’t due to hard disk failure.

– **Automatic backups **– if you only use a second hard disk, you need to back up to it yourself (although with RAID this can be 100% automatic, but then a RAID hard disk is more than $89.99)

– **Web Access – **almost all providers let you access files from anywhere, this alone is a service that is very useful

–** File versioning** – what if you want to get back an older version of a file? Online backup services offer this, at home you are out of luck

**– Security **– your data will be stored in a data centre, which is a lot more secure than at home.

### Conclusion

Whether the extra that online backups offer is worth it for you, is for you to decide. Whether than is worth 400x multiple, is up to you. But all in all, we are only talking about $3.96 per month. Not a large sum to keep offsite backups of all your files.

I welcome any comments at the bottom!

Sweet calculation. Unfortunately you compare the price per year of the harddrive solution to the price per 17 years of the online solution. So your factor 400x is skewed by a factor of 17. So the result is rather around 20x cheaper.

Actually, you could easier calculate this in terms of total prize:

1. HD for 17 years: 90$

2. Online for 17 years: 800$

3. Divide both: ratio = 800$/90$ ≈ 10:1. Online storage is roughly 10x more expensive.

And what others said above, 1 hard drive does NOT provide safety. You’d need 2 of them so that 1 can fail and you’ll then buy a new one. So in 17 years, you might fail, say 3 of them, that would make an investment of 5 hard drives, that would be maybe 400$. So your factor shrinks to 2:1. That’s then not toooo much left.

While on the other hand, most users do store their data at home anyway. So the “additional investment” would be 1 HD. Everytime the normal harddrive of a user fails (if he’d have the data saved online), he’d buy a new one anyway. So the actual investment would really be 1 HD per user life-time. So your factor could indeed be around 10:1.

The decreasing price per GB of harddrives, the decreasing price per GB online storage and the increase of user data should probably stay the same over time. You’ll have 20x more data than now in 10 years, but a 20x bigger HD will cost the same and a 20x bigger online space will be the same. Or whatever the numbers will be.

Considering the 6% data failure rate per year, which is progressive year by year, you actually have a compounded chance to lose the data. First year it’s 6%, second year it’s the first 6% plus another 6% of what’s left (94%*6%), the third year this number becomes 6% + (94%*6%) + 6% + ((94%*6%)*6%) + (94%*6%) + 6% and so on…

After the 5th year you have a failure rate of 50%. Are you considering this to be a good “backup” system where you potentially lose half your data or all of it half the time?

Should your drive be attached to your PC at all times, it will consume less than 5W when not spinning, which is negligible. You won’t access it from another location or be able to share it, but let’s ignore that since you have super backup and restore speeds as well as instant access to all files.

So for a regular HDD that fails after 5 years, or generic failure rates of 50% after 5 years, we can use this new number to compute the backup costs:

– Your on-location HDD: 0.018$ / Gb / Year

– Amazon Glacier backups: 0.010$ / Gb / Year

It seems online backup is cheaper….

I appreciate what you are saying in this particular article.

It’s great to find soemnoe so on the ball

Hard drives don’t last 17 years. Its best to say 5 years. Crashplan has a deal for one payment of $287 you have unlimited data for 4 years. So, your comparison should be more like $358.75 vs $89. (358.75 = 287/4 * 5) That’s a 4x difference, not 400x. If your just running numbers then also include how much electricity costs for 5 years to run the PC holding your 1TB drive. I myself have 2TB of data which makes the comparison even smaller.

Hey Bill,

Good thoughts. I think it’s not just electricity cost but also potential cost if there is a hard drive failure should also be put into consideration. The risk runs higher with local backups, to be honest. But then no one backup method is ultimately reliable, which is why we need to use a combination of local and offsite backups.

Thanks for visiting our site. Would love to hear more of your thoughts on other articles as well .

– Sam