SLA & Uptime Calculator

Check your uptime with the calculator below. You can either insert the duration of the downtime in the first row or the percentage of the uptime in the second row and hit Calculate. It will tell you the length and the proportion of the uptime and downtime.

Calculate Uptime:

Insert the downtime for the last 30 days:

Or uptime percentage for last 30 days:

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What is Uptime?

Uptime is probably the most important single metric you can use to measure the performance of your web host. It shows the time or percentage the service is up and operational. The counterpart of that is downtime. It shows the time or percentage the service was unavailable.

Availability is the same as uptime. It’s often measured by “Nines.” Let’s see how they translate to downtime for 30 days:

Calculations: Uptime Percentage to Downtime

Nines Downtime
99% Two Nines equals to 7 hours and 12 minutes downtime in 30 days
99.9% Three Nines equals to 43 minutes and 12 seconds downtime
99.99% Four Nines equals to 4 minutes 19 seconds downtime
99.999% Five Nines equals to 26 seconds downtime
99.9999% Six Nines equals to 3 seconds downtime

Service Level Agreements (SLA)

Some of the web hosting companies offer a Service Level Agreement. It states the guaranteed level of availability. If the web host doesn’t deliver that uptime level, you will be entitled to refunds or hosting credits. Use our uptime calculator to quickly see if your provider delivered.

Uptime Guarantees

Some web hosts offer real uptime guarantees. Others just say they have a 99.9% uptime guarantee but if you take a look at the terms of service they make you agree with, most of the times you will notice that they do not guarantee it for real. If they don’t deliver the uptime they promised, nothing happens.

Before you start calling your web host that your site is offline, it is a good idea to first check if your website is really offline.

A Trade-Off Between Uptime and Costs

Usually, the higher the uptime guarantee, the higher is the cost. Ideally, you should find the middle ground where the level of uptime gives you peace of mind and the costs don’t go through the sky.

Be wary when a budget hosting company offers 100% uptime. They may believe they can deliver, but in reality, it rarely happens.

Please note: No service provider will have 100% uptime on the long run. They may be up for a couple of months, but sooner or later something always happens. There are just too many things that can go wrong.

Which Web Host Would you Prefer?

  • Host 1 – Offers a 99.5% uptime guarantee in their SLA. They automatically apply any earned credits to your account if the server is not up 99.5% for any given month. The host calculates the downtime by the minute and reports every minute of downtime publicly to all of it’s users and the net at large. Regardless whether you know if the server was down or not, you will get the credits promised.
  • Host 2 – Offers a 99% guarantee. In order to receive the credit you must submit a document detailing your web site’s downtime in writing and this document must be verified by the host. The cost of monitoring their servers to be sure your site is up 99% of the time may be more then the refund is worth.
  • Host 3 – Offers a 99% uptime guarantee. To receive the guarantee their servers must be down 5 consecutive hours. In other words, the host could be down 2 hours on Monday, 3 hours on Friday, and 4 hours on Sunday and you would not qualify for any automatic guarantee credits. They do however state that if you send them documented times of downtime in writing and allow them to compare your findings with their logs, and they match, then you will receive your credit.
  • Host 4 – Offers a 99.999% uptime guarantee. In order to receive the guarantee, you must first enter into a guarantee contract with them. To be able to do this you must go with one of the most expensive packages, in addition to, purchasing extra features that will help your site to remain on-line more often then it normally would. Another words, to receive the 99.999% guarantee it is going to cost you money!
  • Host 5 – Offers a 100% uptime guarantee! Now this one is interesting folks! With Host 5, if your site is down for more then ten minutes at a time (this allows for normal system reboots) they will credit you 25% of your bill! Like the others you are required to submit documentation noting that you’ve found your site down for longer then ten minutes and they must be able to verify this with their logs. Here’s the small print — “No more than two outages per month can be credited.” DOH!

A Few Things to Consider

When you see a host advertising that they have an uptime guarantee, there are a few things to consider.

  1. Never just assume their guarantee means your site will not be down!
  2. Always verify exactly what the host means when they state the offer. Look around on their site to find the details, ask other site owners that are hosted by them if they honor the guarantee, and if the host does honor it, ask how many times a year it must be honored!
  3. Do not just depend on what other site owner tells you. Considering the various plans above, it’s obvious that if the site owner is not monitoring their site 24/7/365, then they may not have a clue whether or not their site was down!
  4. For those hosts that require you to submit your logs of the downtime, ask if, while comparing your records with theirs, will they also credit you for the extra downtime, you may not have realized, but they found during the comparison?
  5. Once you have compiled the above, do they all add up? Meaning: If you have asked the host the same questions you may have asked some of the site owners that are hosting with them, did their answers match?

Uptime Guarantee from Another Perspective

If the host has nothing to lose while your site is down, then their efficiency and speed in bringing the site back up may severely lack. “Put your money where your mouth is” has always made any statement more important to uphold.

An uptime guarantee may only mean a $5 refund for you, but if the host is compensating every site on the server $5/ea (providing their guarantee would force them to do this) then it becomes much more important for the host to keep your site up regardless whether you know about it or not!

Try to assure you have an uptime guarantee while searching for your next host. While doing so, make sure the guarantee is actually what it seems to be. If it does not meet your requirements, email the host and ask them about it. If they are not willing to budge, then continue searching for one that does meet your needs.