When designing a System-on-Chip (SoC) using a Networkon-Chip (NoC), silicon area and power consumption are two key elements to optimize. A dominant part of the NoC area and power consumption is due to the buffers in the Network Interfaces (NIs) needed to decouple computation from communication. Having such a decoupling prevents stalling of IP blocks due to the communication interconnect. The size of these buffers is especially important in real-time systems, as there they should be big enough to obtain predictable performance. To ensure that buffers do not overflow, end-to-end flow-control is needed. One form of end-to-end flow-control used in NoCs is credit-based flow-control. This form of flowcontrol places additional requirements on the buffer sizes, because the flow-control delays need to be taken into account. In this work, we present an algorithm to find the minimal decoupling buffer sizes for a NoC using TDMA and creditbased end-to-end flow-control, subject to the ...