Distribution lead time based on the supply calendar
In Enterprise Planning, the supply lead time for a planned purchase order consists of the following lead times:
- The internal processing time from the Items - Purchase Business Partner (tdipu0110m000) session.
 - The supply time from the Items - Purchase Business Partner (tdipu0110m000) session.
 - A transport time between the address of the ship-from business partner and the receiving warehouse, based on a relevant distance table (if available) in the Distance Table by City (tccom4137s000) session or the Distance Table by ZIP Code/Postal Code (tccom4138s000) session
 - The safety time from the Items - Purchase Business Partner (tdipu0110m000) session.
 
The sum of these lead times is displayed in the Calculated Lead Time (Days) field in the Items - Purchase Business Partner (tdipu0110m000) session.
In addition, the inbound lead time from the Items - Purchase Business Partner (tdipu0110m000) session is used.
Using the calculated lead time
If the order's finish date falls outside the lead-time horizon (defined in the Items - Purchase Business Partner (tdipu0110m000) session), then the start date is computed by:
- Planning backward the inbound lead time using the calendar of the item/warehouse combination (see the Item Data by Warehouse (whwmd2110s000) session).
 - Subtracting the cumulative lead time from the resulting date.
 
Example: purchase lead time based on the calculated lead time
| CLT | Calculated lead time (from the Items - Purchase Business Partner (tdipu0110m000) session | 
| ILT | Inbound lead time (from the Item Data by Warehouse (whwmd2110s000) session). | 
| O/S/E | Outbound lead time / Safety time / Extra lead time. | 
| A | Start date | 
| B | Finish date | 
| C | Requirement date | 
Using planned lead times
If the order's finish date falls within the lead-time horizon, the supply lead time is determined by planning backward each lead time separately:
- The inbound lead time is planned using the calendar of the item/warehouse combination (see the Item Data by Warehouse (whwmd2110s000) session).
 - The supplier safety time is not planned with a calendar, but is interpreted as a number of calendar days.
 - The transport time is planned using the calendar linked to the address of the ship-from business partner.
 - The supply time is planned using the calendar linked to the address of the ship-from business partner.
 - The internal processing time is planned using the department calendar of the purchase office defined for the item/business partner combination.
 
Example: purchase lead time based on planned lead times
| IPT | Internal processing time (from the Items - Purchase Business Partner (tdipu0110m000) session). | 
| SuT | Supply time (from the Items - Purchase Business Partner (tdipu0110m000) session. | 
| TrT | Transport time (based on distance table). | 
| SST | Supplier safety time (from the Items - Purchase Business Partner (tdipu0110m000) session). | 
| ILT | Inbound lead time (from the Item Data by Warehouse (whwmd2110s000) session). | 
| O/S/E | Outbound lead time / Safety time / Extra lead time. | 
| A | Start date | 
| B | Finish date | 
| C | Requirement date | 
No supplier
If no supplier can be found, Enterprise Planning uses the following data to compute a supply lead time:
- The inbound lead time from the Item Data by Warehouse (whwmd2110s000) session, using the calendar of the item/warehouse combination.
 - The supply time from the Items - Purchase (tdipu0101m000) session, interpreted as calendar days.
 
Example: purchase lead time without supplier
| SuT | Supply time (from the Items - Purchase (tdipu0101m000) session). | 
| ILT | Inbound lead time (from the Item Data by Warehouse (whwmd2110s000) session). | 
| O/S/E | Outbound lead time / Safety time / Extra lead time. | 
| A | Start date | 
| B | Finish date | 
| C | Requirement date |