Detailed carbon budgets of plants and organs have become important recently for studies of: translocation rates, the energy required for nitrogen reduction or fixation, flower and fruit shedding, the role of soil respiration as a contributor to crop photosynthesis, possible feedback control by accumulated photosynthate, and partitioning of photosynthate within the plant. One aspect of all such carbon-budgeting efforts has been the determination of dry matter accumulation of a plant or organ, using traditional growth analysis techniques. This chapter discusses mainly the dry-matter rate component of growth analysis. It describes the evolution of a simple field model for predicting dry weight accumulation in a stand of plants that may well be the best dynamic model available for such a purpose. The chapter considers the more detailed morphological growth analyses needed for a whole-plant synthesis. It also discusses the gas-exchange aspects of developing a carbon budget in more detail.