Article 16 of Council Regulation (EC) No 1099/2009 on the protection of animals at the time of killing requires slaughterhouse operators to carry out regular checks to ensure that animals do not present any sign of consciousness following stunning. The Commission therefore considered it opportune to request EFSA to provide an independent view on the indicators and elements for putting in place monitoring procedures, including sampling protocols, at slaughterhouses for different methods of stunning and slaughtering. In order to provide food business operators with an indication on the sample size and frequency of sampling, a mathematical model was developed to calculate the number of animals that need to be checked to fulfil the above mentioned requirements. The model also allows to estimate the potential failure rate given a certain sample size. The model was implemented in a tool with a user friendly interface. This technical report presents this tool and explains its theoretical basis. A user manual is also provided where detailed instructions can be found.