The European Court of Human Rights (ECtHR) declares a single standard of proof (‘SoP’): proof beyond reasonable doubt (‘brd’). Yet the accuracy of this claim and the threshold’s appropriateness have both been challenged. This article uniquely considers and clarifies the Court’s interpretation and application of its SoP. Demonstrating SoP is capable of both broad and narrow interpretations, it shows the Court interprets SoP only narrowly. This understanding confirms brd as the applicable standard, whose use is then considered through detailed examination of the case law. The analysis shows that although the Court’s conception and approach to brd necessarily accommodate some doubt, violations are found with a consistently high level of certainty. There is however, a striking inconsistency in references made to the Rules of Court. Moreover, the Rules do not fully capture the Court’s approach. Addressing this, as the article proposes, would strengthen both the consistency and legitimacy of relevant decisions.