Drear Astghik Pepoyan, Thank you for the site, it's useful for me.

Dear Reyhaneh Ravanbakhsh

You could find a simple calculation at this page

https://www.researchgate.net/post/How_do_we_calculate_the_IC_50_value_in_antioxidant_assays

Dear Gaurav Kumar

Yes, This one is simple, thanks a lot.

ic-50 is nothing but minimum concentration which inhibit 50 % of population.

So try one concentration of your analyte and test it on one group (homogeneous group) and repeat different concentration on different group.

After fixed time interval analysed reduction in number of population.

Plot a graph % survival vs concentration.

calculate from graph concentration at which 50 % population are survived.

Called IC-50