This study on cost elements of REDD+ in Tanzania is based on data from four REDD+ and Sustainable Forest Management (SFM) projects in Tanzania, in addition to an assessment of institutional costs of REDD+ at central government and district levels. Project level data includes: cost-benefit information for the drivers of deforestation and forest degradation in the respective project areas (opportunity costs); data on implementation costs of project activities; and data on the costs for getting REDD+ projects certified according to carbon accounting standards (transaction costs). The report finds that the costs of REDD+ implementation in Tanzania are estimated to range from USD 4.8-13.8 per carbon ton equivalent (tCO2) depending on the location and carbon sequestration rates. The main output of the project is a comprehensive Excel-based calculation tool for project developers and managers.