This chapter describes the photometric calibration of SWS and the expected accuracy. The chapter is organized to follow the general flow of the pipeline processing (see Section 7.3). In Section 5.3 we discuss the method by which the dark current is measured and the uncertainties associated with the dark current measurement. Section 5.4 discusses the Relative Spectral Response Function (RSRF) and the related uncertainties. Section 5.5 presents the application of the internal calibration measurements to correct for sensitivity drifts in time. Section 5.6 presents the pipeline flat-fielding. Section 5.7 discusses the conversion of the internal SWS signal to astronomical units for point sources while Section 5.8 shows how to derive the surface brightness of extended sources. The final section (5.9) of this chapter presents our best understanding of the uncertainties present in the calibrations and in the AAR products of SWS.