Application for calculate the basic humidity of fuel and/or the ignition probability when the user insert the temperature, relative humidity, exposure, slop and other data, with current date and hour of the system or another hour defined by the user. This application is supported the following languages: portuguese, spanish, french and english. This application save an history of the calculations with a identification of the place. This application is developed with official data to the countries in the North Hemisphere of the Earth. The application is useful for those engaged in the investigation of fires or others.