Working capital refers to the capital required for a company's day-to-day business operations and is calculated as current assets minus current liabilities. There are different types of working capital including permanent working capital which is always invested and variable working capital which fluctuates. The objectives of working capital management include maintaining smooth business operations, minimizing capital costs, and maximizing returns on current asset investments. Companies must balance inventory, accounts receivable, accounts payable, and cash levels to maintain a healthy working capital cycle.