The design of the plan of sequential tests by known graphic methods is completed with the creation of the work form, on which the cumulative time of good operation will be represented. The design of the plan of sequential tests through the known graphic methods is completed with the creation of the worksheet, on which the cumulative time of good operation will be represented. But as at the initial moment it is not known how many pieces will be subjected to the reliability test, on the designed worksheet the largest possible ranges of values for the two scales of the graph must be provided, otherwise there is a risk that not all the acquired data can be represented. So the graphic form cannot be judiciously designed. As a result, the paper presents the way in which this problem is overcome by a calculation program designed on the basis of the Microsoft Excel program for the sequential reliability tests in the case of the exponential reliability model, therefore corresponding to the useful life of the products. Data processing is based on the exponential law, and the completion of the sequential test and the result obtained (adequate/inadequate reliability) is based on an algorithm built with logical operators available in the Microsoft Excel program. Another contribution of the work is that it allows the calculation for any values of the predetermined quantities, while the few existing similar calculation programs allow a restricted range of values.