Inventory Reorders: Quantity and Cash Timing

A reorder calculation determines when and how much stock may be needed. A cash scenario determines when the supplier must be paid. Combining them helps expose a common mismatch: a purchase can be operationally necessary before the sales it supports have generated cash. Keep physical stock, inventory position, and payment obligations in separate columns.

Calculate the inventory trigger

Suppose hypothetical demand is 40 units per week, supplier lead time is three weeks, and the business chooses 30 units of safety stock for this scenario. The reorder point is 40 × 3 + 30 = 150 units. This is an entered planning buffer, not a recommended service level. Inventory position includes usable on-hand units plus confirmed incoming units minus committed backorders.

When inventory position reaches 150 units, the example order is 240 units at $18 each, totaling $4,320. Assume the supplier requires 40% at order and 60% before shipment. The deposit is $1,728 and the balance is $2,592. Both percentages use the $4,320 order value as their base.

Test the cash path before confirming the order

Assume the business has $5,000 of usable cash when ordering. After the deposit, $3,272 remains. Another $1,200 operating payment occurs before the supplier balance is due, leaving $2,072. Without an intervening receipt, the $2,592 balance creates a projected $520 gap. The goods may be needed, but the schedule is not yet feasible under these inputs.

An expected customer receipt can close the gap only if it arrives in time. Add its settlement date and test a delay. If the order quantity can change, calculate the revised deposit, balance, and stock coverage together. Reducing an order to solve the cash gap may create a stockout before the next delivery.

Do not confuse the reorder point with the order quantity

The 150-unit trigger is based on lead-time demand and the chosen buffer. The 240-unit order is a separate replenishment decision. Order minimums, case sizes, shelf life, storage space, and demand uncertainty may constrain that quantity. A spreadsheet should not silently set the order quantity equal to the reorder point.

Review the schedule when demand or lead time changes. If lead time becomes four weeks, the same demand and buffer imply a 190-unit trigger. The supplier payment terms may still require cash before receipt. This example does not optimize inventory or guarantee availability; it makes the operational and cash assumptions visible enough to test together.

Method references: OpenStax: Prepare Financial Budgets. Accessed October 22, 2026. All dollar figures are hypothetical worked examples.