Uniformity of money is a topic that has gained increasing attention with the emergence of new forms of digital money. It describes the principle that different forms of money in the same currency are used and traded at par, i.e., at the same value. This economic note shows why uniformity of money is important for central banks and what factors underpin it. The note outlines measures to support these factors and finishes by introducing a layered perspective on the concept of uniformity of money.