1, gross profit margin: gross profit margin = gross profit/sales revenue. Gross profit is the profit after deducting the cost of main ingredients, auxiliary materials, spices, fuel and so on required for cooking in the kitchen. Note that gross profit is not deducted from income tax and circulation cost.

2. Expense rate: I don't know whether you mean total cost or variable cost. The total cost includes fixed cost and variable cost. Fixed costs are generally the depreciation costs of main materials, auxiliary materials, spices, fuels, equipment and tools, while variable costs are, for example, the costs of manpower, logistics and management undertaken by your enterprise.

3. Profit rate: profit rate = surplus value/total prepaid capital. This concept cannot be embodied in a single kitchen operation, because the kitchen is generally equivalent to the production and processing system of an enterprise, excluding other systems such as sales.

4. Net profit: it is net profit. Net profit refers to the company's retained profit after paying income tax according to regulations, which is usually called after-tax profit or net income.

I have worked in a restaurant. I don't think the so-called kitchen management can be measured separately, because these indicators you mentioned need to be related to the front desk sales, finance, procurement and supply system. Closely related to kitchen management are specific indicators such as cost control, pricing support, food quality and food efficiency.