Min-Max vs Reorder-Point Replenishment

Min-max and reorder-point replenishment both fire a restock when stock hits a threshold, but a reorder point pairs with a fixed order quantity while min-max orders up to a maximum, so min-max varies the order size to fill the gap and a reorder point orders the same amount every time. In EDGEBIC by User Solutions the reorder method you choose drives the size and timing of a replenishment suggestion, and the projection reads either method the same way, comparing the projected available balance in each planning bucket against the level you set. This post compares the two, shows when each fits, and grounds the choice in how the parts you actually stock behave.

The reorder method is one lever in the replenishment picture. For the full loop of demand, buffers, and suggestions, read forecasting and replenishment explained, and for the method concept on its own, see what is a reorder method. Inventory features vary by installation, so check which planning capabilities your build exposes.

What Each Method Actually Decides

Every replenishment method has to answer two questions: when to reorder, and how much. The two methods split on the second one.

Reorder point answers when. When the projected balance falls to the reorder point, a suggestion fires. It is paired with a reorder quantity that answers how much, and that quantity is fixed. Every suggestion is the same size, whether stock dropped just below the point or well below it. This is order-a-set-amount replenishment.

Min-max answers both. When stock falls to the minimum, a suggestion fires, and the suggested quantity fills the gap up to the maximum. The order size is not fixed: a bucket that dips just under the min orders a little, and a bucket that has drawn down hard orders more. This is order-to-fill replenishment, keeping stock inside a band rather than adding a set slug each time.

The reorder point glossary and the min-max glossary cover each concept in isolation. The practical difference is entirely in how the quantity is set, and that difference is what should drive your choice.

When a Fixed Reorder Point Fits

A fixed reorder point and quantity fit whenever your order size is constrained, so the same amount should arrive every time.

• Pack or case quantities. You buy in cases of 500, drums of 55 gallons, or reels of 1,000. The order size is dictated by the pack, so a variable fill quantity has nothing to attach to.
• Minimum buys and price breaks. A supplier sets a minimum order or a quantity that earns a price break. You order that amount or you pay more, so the quantity is a business decision, not a fill calculation.
• Economic order quantity. You have worked out an order size that balances ordering cost against carrying cost. That size is deliberate, and you want it repeated.

In all three, the answer to how much is decided outside the projection, and the reorder point simply decides when to fire it. The reorder point should cover demand across the supplier lead time plus a margin, so the fixed quantity arrives before stock runs short. Set it in how to set a reorder point.

When a Min-Max Band Fits

A min-max band fits when your constraint is a level rather than an order size, and you want stock kept inside a range.

• A physical maximum. A tank, a bin, or a shelf holds only so much. The maximum is the capacity, and each order tops off to it.
• Cheap, flexible ordering. When ordering cost is low and the supplier accepts any quantity, filling to a max each time smooths stock without forcing a fixed slug that might overshoot or fall short.
• Steady consumption with a target band. You want the part to live between a floor and a ceiling, and you are happy for the order size to flex with how much was drawn down.

Min-max shines where over-ordering has a real cost (a tank that overflows, a shelf that runs out of room) or where the supplier does not care about order size. It struggles against pack quantities, because the fill it computes rarely matches a whole case.

Comparing the Two at a Glance

Both sit above safety stock, not instead of it. Safety stock is the buffer that absorbs demand variability; the reorder method decides the restock. Keep the safety level below the trigger so a suggestion fires while the buffer is still intact.

A Worked Example: Same Part, Two Methods

Take a purchased seal. On-hand is 300, demand is about 80 a week, and the supplier lead time is two weeks. You want protection so the projection never breaches a floor.

As a reorder point. You buy seals in boxes of 400. Set the reorder point to 200, which covers two weeks of 80 plus a 40-unit margin, and the reorder quantity to 400. When the projected balance falls to 200, one box of 400 is suggested. Every suggestion is a box, which matches how you actually purchase. If demand climbs to 120 a week, 200 no longer covers the lead time, so you raise the reorder point to 280 rather than change the box size.

As a min-max. The seals live in a bin that holds 500. Set the minimum to 200 and the maximum to 500. When the balance falls to 200, the suggestion fills to 500, which is 300 this time. A lighter week that only dropped to 240 would order 260, and a heavier week that dropped to 180 would order 320. The order size flexes to the bin, and the projection flags any bucket that would fall below the 200 minimum.

Same part, same protection intent, two different order behaviors. The projection reads both the same way: it nets demand against supply, shows the projected balance across buckets, and paints the buckets that breach your floor red so you can confirm the restock is timed before stock runs low.

Choosing for Your Shop

Pick the method that matches the constraint on order size, not the one that sounds more sophisticated. If a pack, a minimum buy, or an economic order quantity dictates how much you buy, use a fixed reorder point and let the quantity be that amount. If a physical maximum or flexible ordering dictates a level, use min-max and let the fill flex. Mixed shops run both, part by part, because the right method is a property of the part and its supplier, not a site-wide policy.

For where replenishment sits in the wider planning workflow, start from the EDGEBIC planning guide, and to see how a projected balance actually drives the reorder decision, read how projected balance drives a purchase decision.