# Report Calculations

Hi

I was unable to figure out and explain to my co-peers about how exactly the below calculations in a gatling report are being calculated for a test.I would like to know about 50th Pct,75 Pct and Std Dev are calulated.Below is my test result and injection step.

50th and 75 percentile is calculated as per details shared below.

Based on response time 1) requests are placed in ascending order of response time 2) remove last 50% requests 3) the one you got response time after remove step 2 is your 50th percentile response time.

Normal one has to use this as one of the KPI in performance testing. e.g. 99 % of customer should get response time less than 3 sec. In this case 99th percentile response should be less than 3 sec.

In the case of standard deviation: The thumb rule is if response time of Std.Dev is less than half of the mean, the it is test is considered as good. Else the values are deviated largely outside the mean.

Firstly thanks for the reply mohan…i need a bit clarity regarding this.The answer is perfect but can u exactly say what is the value 121 under 50th percentile indicates…Is that the max value among all those first 50% requests after ascending them in order or it is the avg value of those all 50%?

Yes, it is max value.

e.g.

Request#1 response times

1,2,3,4,5,6,7,8,9,10.

Let assume you would like to calculate 50% percentile response time from above request responses.

Step 1: The response are already acceding order.

Step 2: Remove 50% values from bottom (i.e. 6,7,8,9,10)

Step 3: The 50th percentile value is 5 in the above case.

What it would mean is, 50% of you requests are responded within 5 sec.

Thanks for the information Mohan…