Managerial accounting provides non-financial information to internal managers for planning and control. It differs from financial accounting in its users, time focus, emphasis, and subject focus. Costs can be classified in various ways including by behavior, relevance, controllability, traceability, and function. Managerial accounting systems include job order costing for custom jobs and process costing for mass production. Costs are allocated using plant-wide rates, two-stage allocation, or activity-based costing to assign overhead to products or services.