If the data collected has been scaled to an absolute scale (see DATABSOLUTE), then the molecular weight can be determined knowing the forward scattering, concentration, contrast and partial specific volume of the sample (Jeffries et. al 2016, p.2144 eq. 5).
Determining the MW from absolute scale means that no protein standard is used, and therefore it is not assumed that the partial specific volume and contrast of the sample is the same to that of the protein standard. Therefore, for most accurate results the partial specific volume and contrast should be determined for each sample (Jeffries et. al 2016, p. 2130). If these two values are not known, empirically averaged values may be used (Mylonas & Svergun, 2008).
Input files for databsmw may be in any of the supported data formats as long as scattering vector, experimental intensity and errors are available. The experimental intensities should be on an absolute scale,
for instance those produced by DATABSOLUTE.