If you plan demand in spreadsheets, forecast error shows up on both ends of the balance sheet — lost margin when you stock out on the movers, and cash frozen in overstock on everything else. Most operators never put a number on it. This does.
Transparent, conservative assumptions: stockout-driven lost sales ≈ 10% of your forecast-error rate applied to revenue (a 35% MAPE → ~3.5% of sales lost to stockouts); excess inventory ≈ 30% of forecast-error rate applied to on-hand stock; carrying cost 22%/yr; obsolescence/markdown 12% of excess. Modern planning + AI forecasting typically recovers ~30–40% of the total. These are deliberately conservative ballpark figures to size the problem — a real teardown uses your actual SKU and lead-time data, and usually finds more.
0 = spreadsheet / gut · 3 = systematized. Below 8 means you're leaving the money above on the table.
The fix isn't a bigger spreadsheet. It's a real planning model (one shared number, live data, scenario planning) with an AI forecasting layer on top. Typical results in mid-market manufacturing:
The build path:
Send me read-only access to your current plan (or a sample) and I'll do a free teardown — your actual forecast accuracy, where the cost is hiding, and what's recoverable. You keep the analysis either way.
Book a free teardown →Jason · ex-VP of AI, $250M furniture manufacturer · planning + AI forecasting for mid-market makers