This tool calculates how many concurrent users a web server can support. It is useful for when you want to determine what VPS service you should purchase.
Enter
- Number of CPU cores
- Server response time
- Time in minutes between successive clicks
Background
Number of CPU Cores
This information can be found on the specification page of your VPS provider. If you cannot find it, ask the technical support and they should be able to get you this number.
Server Response Time
You can get this information by entering the URL of any page on your website here. The number to be entered is the one associated with the Time to first byte. Google considers an TTFB number less than 0.8 seconds as Good performance.
Click Interval
This is the time interval in minutes between successive clicks or requests.
The number can be found from Google Analytics by calculating the ratio Average Session Duration/Pages per Session. In the following example it is 61/(60*1.32) = 0.77 minutes.
An e-commerce site might have a click interval of 1 minute.
Use numbers from Google Analytics in the following Calculator. Then use this Click Interval number in the main calculator.
Example Calculation
As an example consider a VPS with 1 CPU core, with a response time of 2.5 seconds and a click interval of 2 minutes. This server can support 48 simultaneous users.