Working capital refers to the funds required for day-to-day business operations and is calculated as current assets minus current liabilities. It includes components like cash, inventory, and receivables. Factors that influence working capital are the operating cycle, business fluctuations, and credit terms. Adequate working capital provides benefits like business solvency and flexibility, while excessive working capital is inefficient and earns low returns. Cash, inventory, and receivables management techniques like ABC analysis help optimize working capital levels.