A computerized method for estimating exhaust noise spectra from a database is provided. The variables considered in the interpolation/extrapolation routine make the procedure particularly applicable to estimating noise from a single-stream jet. The database need not be restricted to data for an isolated single-stream jet but could include installation effects as well as other components of single-stream engine noise. The computation involves a least squares surface fitting procedure that may be of bi-linear or bi-quadratic form. Appropriate weighting of the data is included. To provide a basic prediction procedure for the estimation of far-field@ jet mixing noise from static jet engines with circular nozzles a comprehensive database is provided. The computer program may be run using the provided database or a database generated from the user's own data. A computer program to generate this database is also included.