Par stock calculation — refillable

How much to order, and when

The cost calculator tells you what a format is worth. This one tells you how many litres you need, how many bulk containers that is, and at what stock level to reorder without risking a stockout.

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The quoted supplier lead time is not the real one. Until you have run two actual resupplies, allow plenty: a shower gel stockout in high season is fixed in a panic, at a price that cancels several months of savings.

The property

The baseline for shampoo. The other products are weighted automatically.

Products in the room
Ordering

Absorbs occupancy peaks and lead times that slip. 30% until the supplier is proven.

Leave at 0 if the bottles are already in place. Otherwise the calculation adds the opening par stock.

Annual requirement

bulk containers a year, all products together
Annual volumelitres
Per ordercontainers
Room nights / yearbasis of calculation

Safety stock and reorder point

Safety stockcontainers to keep in reserve
Reorder pointreorder at this level
Coverweeks of consumption

Detail by product

Product Litres / year Containers / year Per order

A worked example, end to end

The calculator's defaults describe a common property: 80 rooms, 70% annual occupancy, 9 ml consumed per night per product, 5 L containers, quarterly ordering, a 3-week supplier lead time and a 30% safety margin, with four products in the room — shampoo, conditioner, shower gel, lotion. Here is what that gives, with nothing typed in.

80 rooms at 70% occupancy come to 20,440 room nights a year. At 9 ml per night per product, weighted by how much of each is actually used, the annual requirement is 607 litres, or 122 containers of 5 L — about 31 containers per quarterly order.

Annual requirement by product — 80 rooms, 70% occupancy, 9 ml/night
ProductRelative useLitres / year5 L containers
Shampoo×1.00184 L36.8
Conditioner×0.70129 L25.8
Shower gel / body wash×1.10202 L40.5
Body & hand lotion×0.5092 L18.4
Total×3.30607 L121.4

On the reserve side: weekly consumption is about 2.3 containers. With a 3-week supplier lead time and a 30% margin, the safety stock is 10 containers and the reorder point is 17 containers — the reserve then covers 3.9 weeks, lead time included. In other words: reorder as soon as stock falls to 17 containers.

For comparison, a property of 150 rooms at 75% occupancy, everything else being equal, consumes 1,220 litres a year — 244 containers, 61 per quarterly order, with a reorder point at 33 containers.

Figures produced by the calculator above, on its default values. Replace them with your own: the consumption assumptions are market estimates, not measurements.

How many 5 L containers should you order a year?

The requirement follows from three figures: occupied room nights, actual consumption per night, and how many products are in the room. An 80-room property at 70% occupancy consumes in the order of 150 to 200 litres a year for a four-product set — thirty to forty 5 L containers.

The margin of error is not in the arithmetic but in consumption per night: that is the first assumption to correct as soon as you have a real reading, ideally from a pilot floor. The four weeks that produce that reading are phase 3 of the switchover plan.

How do you set your safety stock?

Cover the supplier lead time at minimum, with a margin on top until that lead time has been verified on two real orders. A quoted three weeks that turns out to be six, in high season, is paid for in emergency cover — and the extra cost far exceeds what one container held in advance would have cost.

Order more often, or order bigger?

More often, if storage is tight or the supplier is new to you. Bigger, if volume discounts are meaningful and the lead time is proven. Watch the minimum order quantity: some suppliers set a floor that makes monthly ordering impossible.

Why do the products not run down at the same rate?

Shower gel goes faster than body lotion, and conditioner slower than shampoo. Ordering the same quantity of each means stockpiling lotion while the shower gel runs out. The detail by product above applies use weightings, to be corrected with your own readings.

What should you plan for an opening?

Bottles for every room — they arrive full, so the first fill is already covered — the matching holders, and a reserve of containers worth about a month of operation. The first weeks are unpredictable: unstable occupancy, invited guests, press. A stockout in opening week gets noticed more than anywhere else.

Method

Annual volume = occupied room nights × consumption per night × the use weighting of each product. The safety stock covers the supplier lead time plus the margin you set.

  • The use weightings are estimates: shower gel 1.10 · shampoo 1.00 · conditioner 0.70 · lotion 0.50 · hand wash 0.40, relative to shampoo.
  • The calculation ignores seasonality. A strongly seasonal property should reason on its peak month, not on the annual average.
  • Minimum order quantities are not taken into account: check with the supplier that the frequency you choose is compatible with their MOQ.

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