The most popular international test standards for Charpy testing, namely ASTM E23-25, Standard Test Methods for Notched Bar Impact Testing of Metallic Materials, ASTM A370-24a, Standard Test Methods and Definitions for Mechanical Testing of Steel Products, and ISO 148-1:2016, Metallic Materials—Charpy Pendulum Impact Test—Part 1: Test Method, prescribe significantly different tolerances for the specimen ligament length, ranging from ±0.025 mm (ASTM E23) to ±0.01 mm (ASTM A370). The study detailed in this article investigated the influence of ligament length on the absorbed energy obtained from testing reference Charpy specimens at three energy levels (low, high, and super-high). The results obtained and the outcomes of multiple statistical analyses conducted on them support the proposal to revise the ASTM standards to make them consistent with each other and with ISO 148-1 (ligament length: 8 mm ± 0.075 mm).