To ensure that friction in the bearings and axle, and windage losses are within acceptable tolerances, a calibration swing is performed. This calibration procedure involves 11 half free swings of the pendulum where the frictional forces incurred in this short procedure are measured. This procedure is often repeated daily to make sure that energy losses within the system are current and corrected for.

Additionally, the pendulum itself must be verified since the amount of available energy is calculated from theoretical and practical calculations. In simple terms, a full dimensional check is performed to determine the correct amount of stored potential energy in the latched pendulum and also to ensure that the maximum amount of available energy is imparted to the sample. This method of calibration is referred to as a direct verification.

An indirect verification is also required and involves the testing of specimens with certified values to verify the accuracy of Charpy impact machines. These specimens can be NIST Standard Reference Material or can be samples that have been verified on NIST certified Charpy impact machines.