1. A method in a project planning system for specifying durations of project tasks that are not yet completed, the method comprising: receiving from a user a duration value string including a duration of a project task that is not yet completed and including a duration display type, wherein the duration of the project task is a numerical value of time and the duration display type indicates units of the numerical value of time; storing the duration and indication of the duration display type; determining by a processor of a computing system whether the received duration value string includes an estimated duration character indicating that the duration is estimated, the estimated duration character being a single character; when it is determined that the received duration value string includes the estimated duration character indicating that the duration is estimated, setting an estimated flag to indicate that the duration of the project task is estimated; when the duration of the project task is no longer estimated, updating the duration and setting the estimated flag to indicate that the duration of the project task is not estimated; when displaying the duration of the project task and the estimated flag that indicates that the duration of the project task is estimated, displaying an indication of the duration, an indication of the duration display type, and an indication that the duration is estimated; and when displaying the duration of the project task and the estimated flag indicates that the duration of the project is not estimated, displaying an indication of the duration and an indication of the duration display type without displaying of an indication that the duration is estimated.