Working capital is calculated as:

解析

Working capital is current assets minus current liabilities, the short-term money actually available to run the business. Total assets minus total liabilities is owner's equity, which measures net worth rather than liquidity. Revenue minus operating expenses is operating profit, a period result rather than a balance. And cash minus payables ignores receivables, inventory and the rest of the current accounts, so it understates what is on hand to work with.