A computer package QMENF-G was developed in a general form to calculate the optimum amounts and components of quasi-mono-energetic neutron filters and their transmitted spectra in order to meet requirements for different applications in various fields. This code is a complete system to assist the user with input preparation, running calculations and analysis of output results. It is written in standard FORTRAN that runs on any personal computer using windows operating system.As a test case, the components and amounts of elements for producing a neutron filter at ∼3.8keV was calculated using QMENF-G code. It was found that 54 Fe, 80 Se or 90 Zr, can be used as the main components of such filter. However, its transmission, resolution and purity were found to depend upon the accompanying components and their amounts.