99.9% Uptime Guarantee Explained – Know The Facts

March 23, 2012

99.9% Uptime Guarantee Explained

99.9% Uptime Guarantee Explained – Know The FactsTweet This

99.9% Uptime Guarantee Explained

When you are shopping around for a web hosting solution, you will likely see the term “99.9% uptime guarantee” quite often.

Best web hosting companies take this Uptime guarantee clause or promise as a great way to display their confidence in the quality of their hosting.

In fact, Uptime guarantee hosting is being marketed heavily by web hosts and is one of the most important factors in choosing the right hosting provider.

In general, 99.9% Uptime has become a hosting industry standard,

Uptime Guarantee Definition

What is hosting uptime? What is Uptime in Web Hosting?

An Uptime guarantee is your web hosting company’s guarantee that your website will be online for a certain percentage a year.

A good Uptime record means that the web hosting server is working normally without any interruption so that websites on that server can stay up and running.

Any slight interruption in the server’s operation will lead to downtime of all website, email, FTP access, etc.

In another words higher the uptime percentage, better is the host.

100% Uptime means the server will not be down for any minutes in a month.

What Does 99.9% Uptime Really Mean?

What is 99.9% uptime? 

99.9% Uptime means the server may be down for max 0.1% of total number of minutes in a month (Also note that some web host promise 99.9% uptime on a yearly basis).

And if the host cannot meet this guarantee. then it should compensate for the lost minutes. Usually this is done by  adding free hosting credits like additional month of hosting. More details down the article.

Why Uptime Guarantee Is An Important Metric ?

Ideally, as a website owner, you want 100% Uptime.

You wouldn’t want to lose potential clients or customers during peak hours, would you?

So anything short of 100% uptime means bad for business. For a serious business, this means drop in revenue, traffic as well as lost trust from customers.

So good web hosting companies have come up with this standard Uptime guarantee clause to give assurance of their service and reliability.

Uptime Calculation Formula – 99.9% Uptime Percentage Calculation

Let us see what 99.9% uptime means ==> how much downtime in one month?

One month: 99.9% Uptime Calculation:  The total number of minutes in a month x ( (100-99.9)/100)

= 30days x 24hours x 60min x (100-99.9)/100
= 43200 x (0.1)/100
= 43.2 minutes (max downtime) per month

  • One Month: So 99.9% means your website should not be down for more than 43.2 minutes out of 43200 minutes in a month.
  • One Year: And  99.9% Uptime means upto 8.64 hours (43.2  minutes * 12=518.4 minutes)of  downtime Per Year

Please note that this doesn’t mean that you site will be down for some minutes in every month.

Down time may occur due to maintenance work, reboot, troubleshooting scripts on your neighbor website etc.

A  good web host will work hard to keep this Uptime guarantee to maximum possible levels.

Uptime Guarantee Chart – 99.9%, 99.99%, 99.999% Uptimes

Now that we have seen what the standard 99.9% uptime means, let us see more guarantees. 99.9%, 99.99%, 99.999% 99.9999% and 99.99999% Uptime Guarantees.

See the Chart below.

Availability %
Downtime per year
Downtime per month
99.9% (“three nines”)
8.64 hours
43.2 minutes
99.99% (“four nines”)
52.60 minutes
4.38 minutes
99.999% (“five nines”)
5.26 minutes
26.30 seconds
99.9999% (“six nines”)
31.56 seconds
2.63 seconds
99.99999% (“seven nines”)
3.16 seconds
262.98 milliseconds

Source: Wikipedia.org

  1. 99.9% (“three nines”) – This means upto 43.2 minutes of downtime per month
  2. 99.99% (“four nines”) – This means upto 4.38 minutes minutes of downtime per month
  3. 99.999% (“five nines”) – (What does 5 9s mean? ) This means upto 26.30 seconds minutes of downtime per month
  4. 99.9999% (“six nines”) – This means upto 2.63 seconds of downtime per month
  5. 99.99999% (“seven nines”) – This means upto 262.98 milliseconds of downtime per month

What Is Not Covered In Uptime Guarantee

Please note every web host has its own rules for what kind of downtime is covered under Uptime Guarantee.

A few cases of what is not covered in Uptime Guarantee

  • Scheduled or Planned server upgrades or server maintenance does not come under not regarded
  • Downtime caused by natural disasters – flood, hurricane, earthquake and so on
  • Downtime caused by third-party digital software attacks on server
  • Downtime caused by physical attacks a server or data centers
  • Direct denial of service (DDoS) attacks, or hacking attempts
  • User script error: Downtime caused by user scripts, outdated code or due to the installation of third-party applications
  • Downtime caused during user’s DNS and/or IP address changes
  • Downtime caused when user hosting account exhuasted maximum resources that was alloted per hosting plan
  • Downtime during upgrade/downgrade of user hosting account
  • Downtime during technical support requests

Read TOS and SLA to Understand Rules

Again, rules vary from host to host.

So you have to read the TOS(Terms Of Service) and SLA(Service Level Agreement) of the host to under stand this well.

There should be a “Terms of Service” link in footer section of most good web hosts.

Compensation For Downtime

Different hosting companies offer different types of compensation for breaking their own 99.9% uptime guarantee.

You can read their TOS before signing up to learn how web hosts compensate if they could not meet the promise 99.9% guarantee.

For example, SiteGround offers a network uptime guarantee of 99.9%(on yearly basis). If they fall below the guaranteed network uptime, user will be compensated as follows:

“● 99.9% – 99.00% uptime: 1 month free hosting
● An additional month of free hosting for every 1% of uptime lost below 99.00%.”

Uptime Guarantee – What does all this  mean to you?

An uptime guarantee declared by a web host shows confidence. 

When shopping for a web host, read the TOS and look for the details of an uptime guarantee.  This is what matters to you as a site owner.

Shared Hosting Uptime Guarantee – 99.9%

It is really difficult for a shared web host to give a guarantee above  the standard 99.9%, even though shared hosts like SiteGround has been giving 99.99% uptime consistently.

Due to server being shared by multiple accounts, issues can popup. Hence it is kind of difficult to give the guarantee for a shared hosting account.

But at same time, shared hosts are able to give uptime above the standard 99.9% uptime.

This is due to smart software solutions implemented in server to predict or even find issues way ahead of a downtime. This way, server admins are alerted and they can fix even before downtime happens. Server software can correct the issue as well sometimes.

Dedicated Uptime Guarantee – 100% Uptime SLA possible

When a server is dedicated, server software and admins have better control over the server and due to this a few web hosts are giving 100% uptime guarantee for dedicated servers.

Web Hosts giving 100% Uptime Guarantee

LiquidWeb Cloud VPS Hosting with 100% Network Uptime

liquidweb logo cloud vps hosting with 100 percent uptimeLiquidWeb is offering 100% network uptime Guarantee for its dedicated plans as well as Cloud VPS plans.  Webites are protected by 100% Network & Power Uptime guarantees. It also  backs by whopping 1,000% compensation for downtime!

Cost: Cloud VPS Hosting starts at $59 per month.

Get LiquidWeb with 100% Uptime

Web Hosts Offering 99.999% Uptime

Inmotion Business Class Pro Server Plan with 99.999% Uptime.

Business Class Pro Server $14.71/month

With a free no-downtime website transfer from old host, email accounts, complete automatic backups, free SSL, Inmotion Business Pro hosting is feature rich.

With 24/7 USA based Pro Level support, with in-house support technicians and with a 90-day money-back guarantee, Inmotion Business Pro makes lot of sense for small business website hosting.

Cost: Business Class Pro Server Plan costs only $14.71/month.

Get Inmotion Hosting with 99.999% Uptime

Shared Web Hosts offering 99.9% utime and above

Following are web hosts who offer the standard 99.9% uptime guarantee. However, we have given priority for those hosts who have been giving minimal downtime and performed way above the 99.9% guarantee level.

SiteGround – Giving more that 99.99% Uptime

SiteGround is able to give more than 99.99% uptime for its shared hosting plans, thanks to its innovative custom software and advanced web hosting security solutions that helps minimize downtime.

For example, SiteGround gave 99.996% in Last 12 months and 99.999% last month(Taken in Oct 4, 2018).
siteground-99 999 percentage uptime screenshot
SiteGround gave 99.996% in Last 12 months and 99.999% last month(Taken in Oct 4, 2018)

2 Smart solutions by SiteGround that helps minimize downtime.

  1. Linux Containers (LXC): SiteGround platform uses cutting edge LXC technology whch has proven to be highly resource efficient thus gives greater stability during those unexpected traffic spikes.
  2. Pro-active Server Monitoring: SiteGround’s custom built server monitoring software checks the server status far more often than regular server watch systems. This innovative system can detect issues, fix it immediately and as well foresee upcoming issues so that it can handle before the issue happens and thus prevent the issue itself.

Cost: Startup Plan costs only $3.95/month.

Get Sitegroound Hosting


So we saw definition of Uptime Guarantee, different types of 99 percentages, compensation and how uptime is calculated as well.

We also saw which web hosts are giving better guarantees and which ones are the best.

If you liked this article, please support us by sharing as well as linking to this article. Thank you 🙂

99.9% Uptime Guarantee Explained – Know The FactsTweet This