Distributed energy resources (DERs) are a critical component of strategies to decarbonize the electricity sector. As the costs of solar panels and electric vehicles decline, distribution systems will host an increasing number of DERs. Successful implementation requires determining the quantity and types of DERs that can be safely and reliably installed at a particular location within a distribution system. We present a tool that calculates the quantity of DERs that a distribution system can handle with no upgrades. This tool can also help assess the upgrades that can be installed in the network to host more DERs.