Size a Replenishment Review Around the Next Review Date

When stock is reviewed on a schedule, today’s proposed order has to be considered alongside the next opportunity to order. A calculation that covers only the assumed replenishment interval leaves the interval between reviews unexplained. Write the full protection horizon before choosing a target or proposed quantity.

Use a periodic-review order-up-to worksheet to make that decision visible. This is an original administrative planning method with fictional quantities, not a recommendation for any particular review cadence. No actual demand, inventory ledger, lead time or company replenishment rule has been supplied.

Identify what happens at the scheduled review

Record today’s review cutoff and the next planned review date. Define what the review permits: checking the balance, preparing a request, obtaining owner approval or actually issuing a commitment. Those events may occur at different times. The interval assumption must match the decision being modeled.

For the simplified example, assume that an authorized replenishment decision can be made at each scheduled review and that the interval to eligible availability begins immediately then. If actual approval happens later, that delay needs explicit treatment in the timing basis. Do not hide it by keeping the same convenient date labels.

An order-up-to target is a planning level, not a supplier order size. The proposed quantity is the gap between that target and the compatible eligible position, bounded below by zero in this illustration. Actual purchase authorization remains separate, and supplier pack rules are outside this worksheet.

Include the next review plus its replenishment interval

The protection horizon runs from today’s review to the assumed eligible availability of an order placed at the next review. In the teaching model, that is the review interval plus the replenishment interval. Use the same time unit for both and define whether day counts are elapsed or another approved convention.

Assume a seven-day review interval and a ten-day replenishment interval. The combined horizon is 17 days. An order initiated now is assumed available after ten days; an order initiated at the next review is assumed available after day 17. The target evaluates the period until that later replenishment opportunity.

This timing assumption is not evidence that today’s stock will survive the first ten days. Existing eligible supply and dated requirements must still be checked for that earlier interval. A new order assumed to arrive on day ten cannot repair a gap on day four merely because the final target looks adequate.

If the next review moves, recalculate using the revised interval and document the reason. Do not treat a recurring calendar label as proof that a review occurred or that a supplier order was issued.

Build a target from an explicit demand basis

For this simple constant-consumption scenario, the target equals assumed units per day multiplied by the combined horizon, plus an owner-chosen buffer in units. The example uses two units a day and six buffer units: 2 times 17 plus 6 equals a target of 40 units.

These are teaching assumptions. Two units a day is not a measured forecast; six units is not an optimized safety-stock recommendation. There is no probability distribution or service-level claim. A dated-demand approach can use a separately approved non-overlapping demand basis, but do not mix that total with this rate-based scenario unless their membership is reconciled.

Define buffer treatment once. This example adds it to the target, so the comparison position has not separately removed the same six units as protected buffer stock. Similarly, if reservations are already deducted from the position, the target’s demand must exclude the exact covered obligations to prevent duplicate netting.

Compare with a compatible eligible position

For the main example, assume an eligible position of 22 units consisting entirely of eligible, unreserved on-hand stock at today’s cutoff. No inbound or firm-demand deduction is hidden inside that figure. All future scenario consumption is represented in the target.

The proposed quantity is the greater of zero and target minus position. Forty minus 22 gives 18 proposed units. This is the quantity for owner evaluation before separate purchase conditions are applied. It does not round up to a seller minimum, choose a pack multiple or authorize payment.

Under the stated constant-consumption assumption, the initial 22 units would cover the first ten days’ 20 units and leave two just before the hypothetical arrival. Adding the proposed 18 then gives 20; the following seven days consume 14, leaving six at the end of the 17-day horizon. This checks the example’s sequence, not any real product’s availability.

Show how a missed review changes the question

Suppose the next review is moved from day seven to day ten while the assumed replenishment interval remains ten days. The combined horizon becomes 20 days. At the same two-unit rate and six-unit buffer, the target becomes 46 and the proposal against the same 22-unit snapshot becomes 24.

The six-unit increase comes from three additional days at two units a day. This comparison deliberately holds the snapshot fixed to isolate the changed review interval. It is a revised decision at today’s cutoff, not a claim that the balance would still be 22 three days later.

If a current calculation is performed later, refresh the stock position, commitments and demand rather than reusing the old 22. Record both changes: the new horizon and the new snapshot. Otherwise the worksheet can disguise several moving inputs as a single policy adjustment.

Handle inbound and nonpositive gaps explicitly

A real position may include supported unreceived supply. Count its remaining quantity once, exclude receipts already reflected in on-hand and preserve its availability dates. Supply later than the relevant need cannot be treated as an early receipt simply because it falls somewhere inside the full horizon.

If the compatible position exceeds the target, this worksheet gives a proposed new quantity of zero. For example, a position of 43 against 40 produces no additional order under this rule. It does not authorize cancelling three units, returning goods, releasing reservations or disposing of stock. Existing commitments require their own review and authority.

An unknown input is not a zero quantity. Mark the proposal provisional or hold the decision when missing timing, eligibility or demand membership could change it. The arithmetic can be correct while the basis remains unapproved.

Record the review outcome

Retain the cutoff, next review, timing assumptions, target, position bridge and proposed quantity together. Record whether the owner approved the basis, requested evidence or authorized a separate next action. Preserve the purchase decision reference if one is later made.

The completed worksheet explains why this review considered this quantity over this horizon. It does not promise demand, certify stock, establish safe storage or replace the authorization required to buy.

Frequently asked questions

Why include the review interval as well as replenishment time?

This periodic model protects through the assumed availability of an order initiated at the next scheduled review. Seven days until that review plus ten days to eligible availability gives a 17-day horizon. Omitting the first interval answers a different, shorter coverage question.

Is the order-up-to target the quantity to purchase?

No. The target is a defined planning level. In the example it is 40 units, while the compatible eligible position is 22, giving an 18-unit proposal. That proposal remains subject to owner review and separate purchase authorization; no supplier minimum or pack rounding is included.

What happens when the position is above the target?

The illustrated formula bounds the proposed new purchase at zero. It does not generate a negative order or permission to cancel existing commitments. Record the surplus relative to the target and use a separate authorized decision if outstanding orders or allocations need to change.

Can the 17-day target prove there is no earlier shortage?

No. Check dated requirements against supply availability before and throughout the horizon. The example separately tests its first ten days, but actual inbound can arrive too late for an earlier need. A positive end-horizon balance alone cannot establish continuous coverage.