Uptime Calculator

Created by Łucja Zaborowska, MD, PhD candidate
Reviewed by Steven Wooding
Last updated: Jan 03, 2023

Uptime calculator is an efficient tool that will compute the downtime and uptime of your network, based on the uptime SLA percentage (service level agreement percentage).

Wondering what's the exact difference between 99.999 uptime and 99.9 availability? Want to know what's the server uptime calculation formula?

Carefully follow the article below to discover all of that and more! 📺

Uptime - what does it mean?

Uptime is a measurement of a machine's availability and reliability. It describes the period during which the device (usually a computer, or a server) is on and operating.

Uptime is usually given in percentage, but sometimes we tend to omit the percentage (%) sign. You can encounter records that include the 99.97 uptime or 99.99 % of uptime

So what does 99.9 mean exactly? ℹ️

99.9 uptime means that the machine (possibly a server) was working and available for users for 99.9% of the time.

This value is especially crucial for internet-based enterprises or businesses that require fast and reliable networks (e.g., financial operations).

Looking for more time management calculators? Let's try out a few of them:

How to use the uptime calculator?

Our SLA calculator is an exceptionally intuitive tool that requires precisely two steps:

  1. Enter your uptime in %.

  2. Choose whether you prefer to display the precise downtime or uptime of your device/network.

💡 If you want to, you may change the units in which the downtime or uptime are displayed - simply click on the blue-colored elements next to your variables.

For your convenience, our network availability calculator will display your results in detail by default and count them down to 1/100 of the second - look at the grey fields underneath.

🎉Happy with the results? You may also discover the download time calculator.

How to calculate uptime and downtime?

Our uptime/downtime percentage calculator uses the following equations:

Downtime = 100% - Uptime (when both downtime and uptime are given in percentages)


Downtime = 1 - Uptime (when both of these values are given in fractions - you may use our fraction to percent calculator since it works both ways!).

  1. For a daily time in seconds:

    Daily downtime periods = 86400 - (Uptime * 86400)

    Daily uptime periods = Uptime * 86400


    • Uptime is given as a fraction.
  2. For a weekly time in seconds:

    Weekly downtime periods = 604800 - (Uptime * 604800)

    Weekly uptime periods = Uptime * 604800


    • Uptime is given as a fraction.
  3. For a monthly time in seconds:

    Monthly downtime periods = 2592000 - (Uptime * 2592000)

    Monthly uptime periods = Uptime * 2592000


    • Uptime is given as a fraction.
  4. For a yearly time in seconds:

    Yearly downtime periods = 31536000 - (Uptime * 31536000)

    Yearly uptime periods = Uptime * 31536000


    • Uptime is given as a fraction.

Uptime calculations examples

🔅 Let's follow the example of a weekly uptime 99.9 calculation:

We first need to calculate the 100% of seconds in a week:

  • Every minute has 60 second
  • Every hour has 60 minutes
  • Every day has 24 hours
  • Every week has 7 days

Let's multiply all these numbers: 60*60*24*7 = 604,800

The whole week, that is 100% of the time, equals 604,800 seconds.

Our uptime was 99.9%, which is 99.9% / 100 = 0.999 in fractional form.

Let's multiply the uptime fraction by the total numbers of seconds in a week:

0.999 * 604,800 seconds = 604,195.5 seconds

Our server was up for 604,195.5 seconds in a week.

🔅 To calculate the downtime:

Downtime = 1 - Uptime

Downtime = 1 - 0.999 = 0.001

Let's multiply the downtime fraction by the total numbers of seconds in a week:

0.001 * 604,800 seconds = 604.8 seconds

Our server was down for 604.8 seconds in a week.

Is everything done? Let's practice! Calculate the following uptimes:

  • 99.99 uptime, and
  • 99.999 uptime ⏰
Łucja Zaborowska, MD, PhD candidate
Your downtime periods:
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