Two calculations answer two different questions
A reorder trigger asks when to review replenishment. An order quantity asks how much to buy after that review. Our worksheet deliberately keeps them separate. Enter average daily use, replenishment lead time and a buffer in the same base unit. The illustrative trigger is daily use multiplied by lead time, plus the buffer. It is arithmetic on your assumptions, not a forecast or a vendor recommendation. The tool does not estimate variability, service levels or the probability that a supplier delivers on time.
Prepare the stock-position inputs
Enter on-hand stock, already reserved stock and on-order stock that is relevant to the decision. The simplified position is on hand minus reserved plus on order, following the distinction documented by inFlow for its anticipated quantity. The tool does not reproduce every merchant rule, production order or location setting. An overdue purchase order still needs a date review; including its quantity does not make it available to ship today. Use one item and one consistent scope at a time, and do not mix cartons with pieces.
An original worked example
Suppose a fictional business uses four units per day, expects replenishment in six days and chooses an eight-unit buffer. Its trigger is 32 units. It has 25 on hand, 10 reserved and 20 on order, giving a position of 35. That position is above the trigger, but only 15 unreserved units are currently present. If the incoming order is delayed, the purchasing conclusion may change. The example shows why availability and replenishment cannot be reduced to one attractive number. It does not recommend those inputs for your business.
Know when the worksheet is a poor fit
Do not use this simple model as a purchasing instruction for intermittent demand, highly variable lead times, perishable or regulated goods, components shared across production jobs, or operations needing formal service-level planning. Check minimum order quantities, pack sizes, cash constraints and delivery dates separately. Record who supplied the assumptions and when they were checked. No entries are sent to us or saved by this worksheet. The most useful output is often a missing assumption that needs investigation, rather than an immediate order.
Sources used for this page
These records support the facts and comparisons above. Merchant-controlled records are labelled so you can separate product claims from independent evidence.
- inFlow quantity definitions — Merchant documentation · inflowinventory.com · Merchant-controlled · checked 2026-09-24
- W3C: label form controls — Reference · w3.org · Publisher independence not verified · checked 2026-09-24