Introducing the Uptrends double-check

When Uptrends detects an error on your website or server, we always perform a double check on another checkpoint to verify the error. This is why during downtime, you always see a pattern of unconfirmed errors and confirmed errors in your website monitoring dashboards.

Tip: For detailed analysis of the exact measurements we perform, and the errors we detect, please have a look at your Monitor Log report in the Monitors menu.

So, how do you calculate the uptime percentage?

The way we calculate uptime is easy to understand: we take the number of seconds that your monitor was down (in a certain time frame), and divide this by the total number of seconds your monitor was being monitored during that time frame. As a result, we get the downtime percentage, which is then being subtracted from 100% to get the uptime percentage. Pretty simple, ain't it? Let's jump into an example.

Example

Let's say we monitored a website during 24 hours (which translates to 86,400 seconds), and in that timeframe the website went down for 10 minutes (600 seconds). To define the uptime and downtime percentages, we perform the following calculation:

Total number of seconds your website was down: 600 seconds.
Total number of seconds your website was monitored: 86,400.
We divide 600 by 86,400, which is 0.0069.
In percentages, this is 0.69%. This is the downtime percentage.
The uptime percentage for this website would be: 100% minus 0.69% is 99.31%.

Tip: Play around with the data in your account to retrieve the actual seconds. Certain tiles in your dashboards allow you to display the number of seconds of when your monitors were up and down. Hover over a tile, and use the gear icon to expose the different metrics you can select.

Monitor status transitions

We hear you thinking: but how do you mark the time between different monitor statuses (OK, unconfirmed error and confirmed error)? Is the time between an unconfirmed error and a confirmed error being considered as up, or down? You're right, this can seem a bit complicated at first, but actually it isn't. Let us walk you through all the transition periods, and explain how those periods contribute towards uptime and downtime.

OK to unconfirmed error
The time between the two measurements is being considered as up, because we are not sure there is an actual error. For that, a double-check needs to be performed.

Unconfirmed error to confirmed error
The time between the two measurements is being considered as down, because the error is now confirmed.

Confirmed error to unconfirmed error
The time between the two measurements is being considered as down, because the monitor is still in an error condition. A monitor will be in error until we detect an OK indication.

Confirmed error to OK
The time between the two measurements is being considered as down. We start considering a monitor to be up from the moment we detect an OK indication.

Unconfirmed error to OK
The time between the two measurements is being considered as up, because we are not sure there is an actual error. For that, a double-check needs to be performed.

How do paused monitors affect uptime?

When you pause a monitor, this time is being registered as unknown. When the uptime percentage is being calculated, please keep in mind that we include the total number of unknown seconds as well, and mark the unknown time as uptime.

This has been a deliberate choice, because a lot of customers requested this. If you want to exclude the unknown time from the uptime calculation, you can retrieve the total number of uptime seconds to do your own calculation. Various tiles in your dashboards allow you to select these metrics.

How does maintenance affect uptime?

Errors that occur during a maintenance period are excluded from the uptime calculations, as long as you disable monitoring entirely.

Which errors contribute towards downtime?

Please keep in mind that all errors are taken into account when we calculate downtime. Excluding certain errors from generating downtime is on our road map.

For example, when you define performance limits for a monitor and a performance limit is met, we have the possibility to generate an error for that condition. Although your website is not actually down, it will show an uptime of less than 100% because the performance condition was not met.