Stock levels exist to solve one core business problem: how much inventory should you hold at any point in time? Hold too little and production stops. Hold too much and your money is locked up in a warehouse. The five stock levels give you a scientific framework to stay in the sweet spot — and ICAI loves testing this as a 4–6 mark problem where you compute 3–4 levels from a single data set.
Reorder Level (ROL) is where you raise a purchase order. Logic: by the time goods arrive, you shouldn't hit zero. Formula: Maximum Consumption × Maximum Lead Time. It's deliberately conservative — worst-case consumption, worst-case delivery delay. Minimum Level (Safety Stock) is the floor you must never breach. Formula: ROL − (Normal Consumption × Normal Lead Time). The gap between ROL and minimum level is your cushion against surprises. Maximum Level is your storage ceiling — beyond this, costs outweigh benefits. Formula: ROL + Reorder Quantity − (Minimum Consumption × Minimum Lead Time). Average Stock Level is used in cost analysis: either (Min Level + Max Level) ÷ 2 or Min Level + ½ × Reorder Quantity — ICAI frequently uses the second form, so prefer it unless told otherwise. Finally, Danger Level triggers emergency procurement. Formula: Normal (or Average) Consumption × Emergency Lead Time.
The golden thread running through all five formulas is lead time — the gap between placing and receiving an order. Longer lead time pushes up your ROL and minimum stock. Higher demand variability widens the gap between your minimum and maximum levels. Once you internalise that logic, the formulas stop being rote memory and start making practical sense. Think of it as Sharma & Sons Pvt. Ltd. ordering steel rods: if the supplier takes 2–5 weeks, they must survive 5 weeks of peak production without a stockout — that's your reorder level built right there.