EDX analysis can also quantify the elements it detects. A quantitative analysis can be performed by a standards or standardless analysis.

A standardless analysis quantifies the elements by calculating the area under the peak of each identified element and after taking account for the accelerating voltage of the beam to produce the spectrum, performs calculations to create sensitivity factors that will convert the area under the peak into weight or atomic percent.

For example, the spectrum below is of a high temperature nickel based alloy composed of nickel, chromium, iron, manganese, titanium, molybdenum, silicon, and aluminum.

The software subtracts out the background noise in the EDX spectrum as seen below

The software then performs a gaussian fit of the elemental peaks selected. From this it calculates the area under the peaks. Then a calculation is performed. One of the most popular algorithms is ZAF where Z stands for the atomic number of the element, A and F are the absorbance and fluorescence values to compensate for the X-ray peak interaction. From this, the atomic and weight percent are calculated.

                                                                 Element     Atomic %     Weight %
                                                                     Al            2.588            1.203
                                                                     Si            4.247            2.056
                                                                     Ti             0.365            0.301
                                                                     Cr           21.793          19.529
                                                                     Mn            0.229           0.216
                                                                     Fe             3.931           3.783
                                                                     Ni              8.337         59.013
                                                                     Nb               .261           5.221
                                                                     Mo              .249            8.677

Standards quantifications are performed in a similar fashion except that instead of performing ZAF calculations on the areas under the elemental peaks, the areas are compared to standards files which are spectra of the elements to be quantified acquired under the exact conditions of the unknown spectrum. Since it requires these additional spectra, this form of analysis is more time consuming and generally is not more accurate than a standardless quantification unless the X-ray peaks of the elements to be quantified overlap or the elements are in trace quantities.

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