Long Lead Item Float Calculator

Long lead items govern schedule start.

Order week (from start)

Delivery week

Install start week (needed)

Schedule total weeks

Float weeks

Lead time weeks

Critical path risk

Medium

How the math works

Lead = delivery − order. Float = install start − delivery.

Lead 24 weeks. Install starts week 32, delivery week 28. Float 4 weeks — moderate risk.

How to Use

Enter order week.
Enter delivery week.
Enter install start week.
Enter schedule total weeks.
Read float for item and critical path risk.

Frequently Asked Questions

What's long-lead?

Items with lead times 20+ weeks. Typical: elevators, generators, switchgear, custom steel, specialty HVAC. Must order before design is finalized — design-build or design-assist typical.

Impact?

Each week of delay = critical path delay (usually). Pushes SC directly. LDs trigger. Rent/interest carry. Costs can be 10-20x the item cost on long delays. Engage vendor early in design.

Mitigation?

Lock vendor commitment with deposit early. Order long-lead first (before design final). Parallel design of support systems. Shop drawings fast-tracked. Strong procurement management. Make long-lead procurement a separate scope.

How does this interact with the rest of the capital stack?

Each tier of the stack affects the next. Senior debt constrains LTC and DSCR. Mezz and pref consume equity spread. Interest rate hedges protect DSCR but cost premium. Always model the full stack holistically — optimizing one tier alone often degrades another. Institutional underwriters run three or four scenarios across the stack before committing capital.