What does 99.9% uptime mean?

what is 99.9% uptime

When you choose a web host (choose me!), and they tell you that they have 99.9% guaranteed uptime, it sounds like your site is going to be available come hell or high water, right?

Not quite.

If you run a site monitor (and you should – see my post here), you might be aware that 99.9% uptime is actually not quite as reliable as you would imagine.

What is 99.9%?

Let’s take an average month of 30 days – and I’m rounding up in the following calculations:

30 days x 24 hours x 60 minutes = 43,200 minutes in a month (who said they never have enough time?)

99.9% of 43,200 = 43,157 minutes

Which means a grand total of 43 minutes downtime.

Every month.

And that’s before you factor in any planned maintenance.


But don’t panic. Server downtime happens very frequently, it is usually brief, and it really isn’t the end of the world.

What does it mean for you?

Unless it is absolutely critical that your site is up 24/7 (hint: rarely is this the case), then 99.9% uptime is just fine. You aren’t going to lose all your visitors, and your SEO will not be tanked if your website disappears for ten minutes here and there through no fault of your own.

So relax. Some of the biggest companies online run with 99.9% uptime, so you are in good company.

Pop a monitor on your site and when you get a notification of downtime, put the kettle on. By the time you’ve made a cup of tea, your site will probably be back and you’ll have saved yourself a whole lot of worry.

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