Looking at population’s behavior by taking samples is quite uncertain due to its big and dynamic structure and unimaginable variability. All quantitative sampling approaches aim to draw representative sample from the population so that the results of the studying samples can then be generalized back to the population. The probability of detecting a true effect of a study largely depends on the sample size and if taking small samples will give lowers statistical power, thus having higher risk of missing a meaningful underlying difference. There have lot of online sample size calculators which are based on population size, allele frequency which tell us about the number of samples required for the study but none will help in setting a threshold for the availability of the sample from a single hospital in a particular period. This study aims to provide an efficient calculation method for setting a threshold for the availability of samples during a specific period of a research study which is an important question to be answered during the research study design. So we have designed a spreadsheet-based sample availability calculator tool implemented in MS-Excel 2007.