Net loss definition including break down of areas in the definition. Analyzing the definition of key term often provides more insight about concepts. The term net loss can be defined as: Excess of expenses over revenues for a period. Net loss is generally calculated on the income statement with the equation of revenue less expenses. A net loss happens when the expenses are greater than revenue. Usually, hopefully, revenue is greater than expenses in most cases resulting in net income but if the expenses are greater than the revenue we need to remember to change the bottom line from net income to net loss.