UPVC Inventory Excel Formulas

I already keep my UPVC store stock in Excel, but the sheet is little more than a long table. I now need it to do the thinking for me. Specifically, I want formulas—at an intermediate level—to pull in correct quantities, flag re-order points, and cross-reference items across multiple tabs so I always see the right stock figure at a glance.

The job centres on VLOOKUP (or XLOOKUP if you prefer), IF and related conditional logic. No data entry is required; the raw figures are in place. What I need is the formula layer built, tested and explained so I can maintain it myself later.

Deliverables
• Fully functional workbook with all requested formulas in place
• Brief in-sheet notes or a short Loom/video walkthrough showing how each key formula works

When I can update a single cell on one tab and see accurate, instant totals and low-stock alerts everywhere else, we’re done.