Evaluations and value-based decisions are often accompanied by a feeling of confidence about whether or not the evaluation or decision is accurate. We argue that this feeling of confidence reflects the variation of an underlying value distribution and that this value distribution represents previously experienced values related to an object. Two preregistered experiments in which the variation of such value distributions was systematically varied provide causal evidence in favor of this hypothesis. A third preregistered experiment showed that, for natural food items with uncontrolled prior experiences, confidence in evaluations is again related to the variation of individuals’ self-reported value distributions. Similarly, for choices between items, the variation of experienced values related to a choice pair influenced confidence in the perceived correctness of the choice. These findings converge with other domains of decision making showing that confidence tracks the variation of the underlying probability distribution of the evidence that a decision is based on, which in the case of value-based decisions, is informed by a value distribution reflecting priorly experienced values.