Website availability: what is it?


"My website must be available day and night, seven days a week."

"My website should be available 99.9% of the time."

Customers often ask for 100% availability of their site, without realizing what it actually entails. Should websites be available 100% of the time? Is 100% uptime achievable?

Customers often ask for 100% availability of their site, without realizing what it actually entails. Should websites be available 100% of the time? Is 100% uptime achievable?

While disregarding website availability as a major element of user experience is a surefire path to drive visitors away, before asking for absolute availability, we must understand what it means and how to calculate it. We will also go over what factors can negatively impact your website’s availability, the ones you can plan and others that may come when you least expect them.

So let’s start by what site availability actually means.


The definition of website availability

In simple terms, availability means that you can access a website by entering the website's URL in your browser or clicking on a link that points to your site (on social media, email, another referral website, etc.) and the site is showing the content as expected.

Availability refers to the "uptime" of a website, which is often directly related to the uptime of the web servers your site is hosted in.

The availability of a website is often expressed as a percentage.

But, is website availability the same as website performance? Website performance can be defined as the time that it takes a website to load. This term is often adapted and tweaked to fit each business’ needs.

Website availability can be measured in different ways, depending on what is considered a loaded page - just text and no buttons? Everything on the page loaded? Also, what factors could impact loading time – for example, cache download or heavy files.

Both availability and performance are key elements for user experience. In my opinion, not performing is the same as not available. Then what criteria should be kept in mind when checking for availability?

  • How many seconds should it take to load a certain page on your website?
  • What page within your website should you use to measure performance?
  • How will you measure it?
  • What is the measurement time interval?


How to determine your website’s availability

Measuring the availability of your website gives you insight into the uptime and downtime and if those were planned or unplanned.

By understanding what affects your downtime and identifying frequent causes, you’ll be equipped to improve on the areas you’re lacking and ultimately maximize your website availability.

The availability of a website is often presented as a percentage. It’s calculated dividing the uptime by the total period of time you’re analyzing.

A monthly Service Report will say, for example, "the website was 99.98% available this month". The 0.02% missing come down to about 20 minutes when it couldn't be reached by visitors that month. This is what is often called “downtime”

There are a lot of tools on the market that can help you with calculating this percentage. New Relic can provide insight about the percentage of uptime and track it, but also offers customer error recording and transaction tracking. However, there are also other tools like Pingdom offer free accounts that can be very beneficial for high level insights into your website’s availability. 

Depending on your type of hosting service or provider, you may need to check the availability yourself, or your managed hosting services partner will be responsible for optimizing your website’s availability as well as aspects like security, capacity and performance.


What factors can impact on your website’s uptime

The uptime percentage of your website can be influenced by several factors, planned or unplanned, internal or external. Whether the downtime was planned or not makes a big difference in the way your results can be analyzed.

1. Planned maintenance:

  • Changes and fixes on your website or web content management system (WCMS) - adding new components to your authoring environment, implementing a new page layout, changing branding elements such as colors, logos, etc. and so on;
  • Planned maintenance on your server or hosting infrastructure - typical examples are implementing software patches or memory upgrades.

All systems need maintenance, so you should take this into account when managing your website’s availability.

If you ask for 99.99% availability, be aware that you only have 4.32 minutes out of a whole month to handle the factors above, which is not a lot. However, this type of planned activities are usually purposefully left out when calculating the uptime percentage.

2. Unplanned factors:

  • Attack on your website
  • Hardware & software failures
  • Natural disasters, such as power cuts, fire or flood in your server room


A good hosting provider will have systems in place to mitigate these risks and minimize their consequences if any damage is done.

Last but not least, integrations with other systems or vendors can heavily impact your website's availability. Web development has evolved a great deal over the last couple of years, making a lot of excellent services available.

Adobe Fonts is a good example of such a tool: it integrates nice looking fonts on your website. When you incorporate a service like this, you have to keep in mind that it can sometimes fail. A failure or poor performance from these kinds of software can take a toll on your website’s uptime.  


On a side note: the servers are up... all green?

While being warned when your website is down is necessary - investigating the cause of downtime should not be your task if you’re working with a managed hosting services partner.

As a web consultant, when a problem occurs and I have to talk to external hosting providers, "all lights are green" is often the response. Servers may be up and running, but that's not a guarantee that everything is working as it should. My advice: have everything written down in one contract, so finger pointing is excluded. It will save you a lot of hassle.


Final Thoughts

100% website availability might seem like a desired number, but when you understand all the elements contributing to your site’s uptime, it’s clear it’s a close to impossible goal.

This means that, even if it isn’t reasonable to aim for such a high percentage, you should pay close attention to what can impact it negatively. In practice, this means planning your website and server maintenance, choosing reliable hosting providers, but also carefully considering the tools and services integrated in your website and WCMS.