When a company generates more revenue than it pays out in cost/expenses for any given period, it generates a profit. Company management, analysts and investors use a multiplicity of profit calculations that deduct subsets of expenses to arrive at different iterations of profit. Net profit (which can be expressed pre or post tax) is any money remaining when all costs have been deducted. Operating profit is revenue (less Cost of Goods Sold) minus operating expenses (cf.), depreciation (cf.) and amortisation (cf.) before deduction of tax and interest. Gross profit is net sales revenue minus Cost of Goods Sold before operating expenses and interest expense.