What it is
Lead time is how long a supplier takes, in days, from the day you order to the day the goods land at one of your warehouses. It is the figure the replenishment engine walks against: a line is short when its stock runs out before an order placed today could arrive, so the lead time decides when Tightly asks you to order.
How Tightly decides it
The engine and the Bench read a lead time from the most specific level on record, in this order: this variant at this supplier and warehouse, then this supplier at this warehouse, then this variant at this supplier, then the supplier's own single figure, and last your default. Your default is the number Tightly assumes where nothing more specific is on record; it is the Default lead time in Settings › Planning. A supplier's lead time is per warehouse: the same supplier can take three weeks to one warehouse and five to another, so the supplier faces read the per-warehouse rows, each one the supplier's own figure for that warehouse or else your default. A variant's lead time at a supplier is the most specific level, for the case where one product ships differently from the rest of that supplier's catalog.
The source word, never the number, says which level a figure came from. A figure that is your default carries the words from system; in Variant suppliers a supplier's own figure reads this supplier and a variant's reads this variant at this supplier. Where several warehouses carry a value, a face prints the range as the shortest and the longest figure, as in 21 to 35 days, or one figure when they agree, with each warehouse and its days on hover.
Lead time also sets how far the engine walks. Each line is walked at least 120 days, and where its forecast reaches further, past its own lead time plus your cadence, so a long sea import is covered past the standing horizons. On Lite and Essentials, Smart Replenishment offers one more horizon when your longest lead time runs past the standing ones.
A supplier's own consistency, not only its average, feeds the buffer the replenishment engine holds: a supplier whose delivery days swing widely earns a deeper safety stock than one who always lands on schedule for the same average lead time. That spread is worked out from the supplier's own purchase order receipts over the last two years, order date to delivery; a supplier with fewer than five counted receipts, or a transfer between your own warehouses, takes a documented default spread instead.
The words on the face
| Word | Where | What it means |
|---|---|---|
| a range in days | Suppliers, The supplier, its Catalog, Variant suppliers | The shortest and the longest figure over the warehouses that carry a value; one figure when they agree |
| from system | under a figure, and in a lane of the supplier's Edit drawer | Your default stands in; nobody has given this supplier's own |
| this supplier | Variant suppliers, Source | The supplier's own figure for that warehouse |
| this variant at this supplier | Variant suppliers, Source | An override for one variant |
| Not set | Variant suppliers; the hover on a dash in Suppliers | No level carries a value |
| No lead time | Suppliers, the figure row | Suppliers whose own single lead time is empty, whatever their warehouse rows show |
| Lead time not set for {n} variants | The supplier, Needs a person | Variants at this supplier with neither their own lead time nor the supplier's single figure |
What you can do about it
Set the default in Settings › Planning. Set a supplier's lead time by warehouse in the supplier's Edit drawer: a lane reading From system takes Set to give it its own days, and Clear drops a lane's own days so the default applies again; only the lanes you change are saved and the rest are unchanged. Set a variant's lead time at a supplier in Variant suppliers, the same way. On the supplier's record, Needs a person counts the variants as Lead time not set for so many variants, with Set as its door to the Catalog narrowed to them. A refusal names your warehouses in the server's words:
Locations do not exist:
Glossary line
Lead time is how long a supplier takes, from the most specific level on record.