Abstract: A thermometer having a symmetrical probe with a sensor for sensing temperatures and a processor, a method for calculating temperature of an object by a second-order differential equation comprises the steps of obtaining temperatures from object, performing a first temperature calculation to obtain an initial prediction of temperature of object, adding a compensation coefficient, generating a compensated temperature based on a combination of initial prediction of temperature of object and compensated coefficient, and calculating a stabilized prediction of temperature of object based on compensated temperature before sensor has reached temperature of object. This thermometer can effectively decreasing error during heat transfer process.