Two experiments investigated the relationship between subjective interpretation of frequency terms and corresponding objective values. Evidence supported the existence of a nonlinear relationship that is well described by a logarithmic function. The general form of this relationship was consistent across different methods of eliciting subjective frequency estimates and different frequency response scales. These findings, in combination with prior research, suggest that individuals can be highly accurate in reporting the frequency of prior experiences but that subjective reports using common frequency response scales and scoring methods should not be taken to reflect equal intervals of actual frequency. This bears similarity to psychophysical relationships observed between sensation and stimulus intensity, and it has implications for the interpretation and analysis of self-report measures that use Likert-type frequency response scales. (Contains 2 tables, 2 figures and 4 footnotes.)