Schedule Lead Time is the period allowed for the completion of a work: a time between placing an order and delivering the final product. Schedule lead time is an amount of time which a process or project takes between being initiated and completed, or a time to elapse until something takes place. This amount of time may have certain leeway, from the minimal amount of minutes, hours, or days, etc, to the maximal one – the allowance of variation is reasonably defined from some factors which are fully or partially out of acceleration (cannot be speeded up). This term is often used in supply chain management, project management, manufacturing, etc.
Calculation of lead time includes considering a number of smaller links lying between the initiation of a process and its completion: every link has its own time limits which may vary within limits. By calculating a sum of the minimal durations and of the maximal durations of these intermediary steps, the minimal and maximal lead time can be derived, so a process managers may say to clients: “delivery of your order will take from X (min time) to Y (max time) days, so please wait”.