Net working capital or working capital is defined as current assets minus current liabilities. Therefore, a change in the total amount of current assets without a change of the same amount in current liabilities will result in a change in the amount of working capital. Similarly, a change in the total amount of current liabilities without an identical change in the total amount of current assets will cause a change in working capital.
For instance, if the owner makes an additional investment of $20,000 in her company, the company's total current assets will increase by $20,000 but there is no increase in its current liabilities. As a result, the company's working capital increases by $20,000. (The other change is an increase in the owner's capital account.)
If a company borrows $50,000 and agrees to repay the loan in 90 days, the company's working capital has not increased. The reason is that the current asset Cash increased by $50,000 and the current liability Loans Payable also increased by $50,000.
The use of $30,000 to buy merchandise for inventory will not change the amount of working capital. The reason is that the total amount of current assets will not change. The current asset Cash decreases by $30,000 and the current asset Inventory increases by $30,000.
If a company sells a product for $3,400 which is in its inventory at a cost of $2,500 the company's working capital will increase by $900. Working capital increased because 1) the current asset accounts Cash or Accounts Receivable will increase by $3,400 and Inventory will decrease by $2,500; 2) current liabilities will not change. Owner's equity will increase by $900.
The use of $100,000 for the construction of a storage building will reduce working capital because the current asset Cash decreased and a long-term asset Storage Building has increased.