A businessman is often faced with the challenge of making decisions based on probabilities. In many situations the analyst is obliged to assume a normal distribution to simplify the calculations, or the analyst has no sufficient knowledge or tools to perform normality tests or a test of goodness to check if the data fits to some other probability density function.         The purpose of the "Universal Probability Calculator" is to calculate the probability of taking a value greater or less than a specific value, given a set of data. The method does not demand statistical knowledge from the user, there is no need of normality assumptions, goodness test or transformations. The proposed method is easy to be used, robust and many experiments have evidenced its quality.  The tool is implemented in VBA Excel, so it does not require any installation and it has a friendly interface.                 In the business world, both in manufacturing or service operations it is common to collect a sample and then calculate probabilities that will support the decision making process. In many cases, it is desired only to calculate the probability in a simple and quick way and there is no time or software to do deeper analysis. For example in industry, it is possible to process a lot of parts in one machine and then estimate the yield of that machine given a specified value. Or in a bank, given a sample of the waiting time of the clients  in the line, it desired to calculate the probability to have a client waiting more than a value specified by the law. The interface of the tool is seen below in the figure 1.         Figure 1: Interface         Considering it is an Excel tools, there is one specific spreadsheet (1 column) to store the data set with the samples. After that, the user just needs to specify in the yellow columns the values for which is desired to calculate the probability of taking a value less than it, it means, P(X < x).         The interface is explained in the figure 2. Figure 2: Interface                 The left side of the figure 2 has the data set with the sample.  The field 1 has the cells where the user should specify the values x to calculate the probability P(X < x). The field 2 is the result with the value of the probability. The field 3 gives an important information about the quality of the result, it gives the estimated confidence level for the confidence interval specified by the user in the first row of the column. For example, for the value x=80,it is 94.1% confident that the true probability value is in the interval [12.2 - 4.0; 12.2+4.0] , or [8.2; 16.2]. The confidence interval is specified by the user and the tools will calculate the confidence level.  Naturally, the higher the sample size, the higher the confidence level.         The arrow 4 indicates the button the user needs to press in order to calculate the probabilities. The field 5 gives information about the first four moments of the distribution: mean, standard deviation, skewness and excess kurtosis. If the skewness and kurtosis are close to zero, the closer to a normal distribution the data is. In order to give a quantitative information, a normality test based on " Pearson - D'agostino Test" is performed  and the p-value is calculated. Usually, a p-value < 0.05 means the data does not follow a normal distribution.         Finally, the arrows 6 and 7 indicate the histogram and the cumulative probability function for the data set.         You can buy the tool for only US$ 2.00. The file will be sent to you via email in 2 days. For additional support, submit the form by this link.