When you outline your project, some data are known, and others have to be estimated. The first important thing to do is to try and make your estimations as accurate and sure as possible. For the investment part, see to it that everything is included in your calculations and double-check by calling for tenders from several potential suppliers (see example below “Cost Calculation Bürstadt"). You will mostly know the costs of the biggest investments (building, land, most important devices and facilities, etc.). As for the revenue forecast, make your market study as accurate as possible, not too optimistic as to sales prices, competitors, customer behaviour, etc. A good way to make reliable estimations is to double-check if each forecast figure of each line of your calculation file is realistic. If you can find state-of-the-art examples or business experiences to base your estimations on, do not hesitate to use them. Besides forecasting the operation of the business with hypotheses that you find realistic, a way to secure the business is to make a worst-case forecast. This means that the P&L and cash forecasts are based on the most pessimistic hypotheses. The idea is that if the business keeps its P&L and cash balance with pessimistic hypotheses, it should be very safe in reality.