This paper will discuss the importance of preparing the change of production plan during uncertain time using linear forecasting (FORECAST.LINEAR). As we all know, in this era of uncertainty, especially since the COVID-19 pandemic, many company production schedules cannot meet the demand of customers. Many manufacturing companies are in shock because of the pandemic, from the uncertainty of government regulation and the scarcity of raw material because of the demand for each production plan between companies. Companies are confused and overwhelmed to make decisions, especially for companies in the manufacturing sector in adjusting the production level. In addition, uncertainties can come any time, and not only about a pandemic or epidemic, but can be a monetary crisis or other kind of uncertainties. In addition, adjusting the production level severely affects the supply chain and other companies who produce parts or gather materials, since these companies also need to adjust their production level. From this study, we hope that a better way to adjust production level including preparing for every uncertainty could be used for better decision making in forecasting the production plan and could be used for shifting production plans when adjusting to government regulation and customer demand.