Despite decades of academic work and practical management applications, the concept of visitor capacity remains controversial and inconsistently operationalized. Nevertheless, there are situations where development of a numerical estimate of capacity is important and where not doing so has resulted in land management agencies being successfully litigated. This report is a guide to developing estimates of numerical visitor capacity, with particular emphasis on wilderness. It reviews capacity concepts, surveys available approaches to capacity determination, and outlines a generic process. Appendices provide information on relevant legislation and policy, as well as detailed examples and templates.