When you’re shopping for a hosting company to host your website, can you be assured that your website will always be up and viewable?

Uptime is a measure of how well the web hosting provider is doing at keeping their systems up and running.  If a hosting provider has a high uptime percentage, then it would mean that their servers stay up and running and so any site you host with them should stay up and running too.  Typically you’ll see a hosting company state a guaranteed “99.9% uptime.”  This is the industry standard.  To be realistic, there is no 100% guarantee.  Things happen, but you can get pretty close.

Uptime is simply calculated as a percentage of time:

  • 98% uptime = 28.8 minutes/day or 3.4 hours/week or 14.4 hours/month or 7.3 days/year
  • 99% uptime = 14.4 minutes/day or 1.7 hours/week or 7.2 hours/month or 3.65 days/year
  • 99.5% uptime = 7.2 minutes/day or 0.84 hours/week or 3.6 hours/month or 1.83 days/year
  • 99.9% uptime = 1.44 minutes/day or 0.17 hours/week or 0.72 hours/month or 8.8 hours/year

Sometimes there are scheduled outages where the company plans to perform a server upgrade or planned hardware change out.  This downtime is not covered in their uptime guarantee.  They try to do it in the hours between midnight and 5am to minimize impact on businesses, under the assumption that the majority of them are closed for the night.

And, of course, there are the unscheduled outages caused by failed hardware or in the unfortunate case of an attack by some malware or trojan whose basic goal is to take down a network, site or service.

The guarantee does allow for compensation should your downtime exceed the stated value, however most hosting providers have a lot of hoops they want you to jump through to claim the reimbursement.  They are probably hoping that you will decide that the amount of effort involved is not worth the minimal amount you would qualify to receive.

Regardless, 0.1% of downtime is actually very minimal.  It is in their best interest for reputable companies to do their best to minimize any downtime.  Like any other business, it comes down to the overall service you receive that will determine whether or not you trust and continue your relationship with that company.