The 2006 Fining Guidelines are the reference point used by the European Commission (Commission) to determine penalties imposed for breaching EU competition (antitrust) law (Articles 101 and/or 102 TFEU). This Practice Note details the Commission’s approach to calculating fines, recent case law, and a step-by-step guide on how the Commission calculates fines. There is also an exploration of general principles of EU law which the Commission is required to observe when setting fines, as well as who is liable for penalties (such as parent company liability) which will impact the magnitude of fines.