PurposeThe pain beliefs and perceptions inventory (PBPI) and the pain catastrophizing scales (PCS) characterize beliefs or distress dimensions of the pain experience. It is relatively unknown, however, to what degree the PBPI and the PCS are well suited to classifying pain intensity.MethodsThis study applied a receiver operating characteristic (ROC) approach to these instruments against the criterion of a visual analogue scale (VAS) of pain intensity with fibromyalgia and chronic back pain patients (n= 419).ResultsThe largest areas under the curve (AUC) were moderate and limited to the constancy subscale (71%) and total score (70%) of the PBPI and to the helplessness subscale (75%) and total score (72%) of the PCS. The best cut-off scores for the PBPI and PCS were better off at detecting true negatives than true positives, with larger specificity than sensitivity values.ConclusionWhereas, the PBPI and PCS are certainly useful instruments to evaluate diverse pain experiences, they may be inappropriate to classify intensity. The PCS performs marginally better than the PBPI for classifying pain intensity.Supplementary InformationThe online version contains supplementary material available at 10.1007/s11136-023-03444-8.