Overview
The progress of opportunities in business is captured in a Sales Stage field. For revenue line item-enabled instances, the Sales Stage field is available on revenue line items. Other instances will display this field on opportunities records. This article covers the default values for the Sales Stage field and their suggested meanings. To edit or add to the default list of sales stages, please refer to the Adding Custom Sales Stages and Probabilities to Opportunities article.
When you select a sales stage in the revenue line item record, the system automatically populates the corresponding probability value (e.g. 10, 20, etc.) in the Probability (%) field. These probability values are a useful tool as it helps calculate and predict your sales forecast for a specified time period. For more information on forecasting, please refer to the Forecasts documentation.
Suggested Definitions
The probability value and definition of the default sales stages are as follows:
source http://support.sugarcrm.com/Knowledge_Base/Opportunities_Forecasts/Understanding_Sugar_Sales_Stages