The BioCCP.jl package (Julia) exploits the Coupon Collector Problem for sample size determination of screening experiments in combinatorial biotechnology. Context: During the combinatorial engineering of biosystems such as proteins, genetic circuits and genomes, diverse libraries are generated by assembling and recombining modules. The variants with the optimal phenotypes are selected with screening techniques. However, when the number of available modules to compose biological designs increases, a combinatorial explosion of design possibilities arises, allowing only for a part of the libary to be analyzed. In this case, it is important for a researcher to get insight in which (minimum) sample size sufficiently covers the design space, i.e. what is the expected minimum number of designs so that all modules are observed at least once.