How much inventory a bin store needs, worked out by formula

How much inventory does a bin store need each week?

Multiply your number of bins by the units one full bin holds, then by how many times you fill them in a cycle (the restock plus mid-week top-ups). Divide by the share of each load you can actually use, and subtract any leftovers you put back. Convert the result to pallets or truckloads using the units per pallet of your own loads.

There is no universal answer like "two truckloads a week", because bins, goods and crowds differ. The formula below gets you a real number in an afternoon. For the wider business, see the pillar on bin stores, discount stores and jobbers.

The formula

Use these letters:

Units needed on the floor per cycle = B × U × (R + T) − C

Units to buy per cycle = units needed ÷ S

Pallets per cycle = units to buy ÷ P

That is all. The hard part is getting honest values for U, S and P.

Step 1: count a test bin

Take goods from a real load, not your best pallet, and fill one bin to the level you want shoppers to see on restock day. Count every unit. Repeat on two or three bins, ideally from different pallets, and take the average.

Fill level is a choice. Heaped bins sell the treasure hunt but use more stock. Level bins use less. Decide the standard, photograph it, and train the crew to fill to the photo.

Step 2: decide your fills per cycle

R is usually one full restock per week. T is the mid-week topping up. Some stores add a little fresh stock on a middle day to keep the bins interesting; others let the bins thin out as the price drops, which is part of the ladder's logic. If you top up with a quarter of a fill once, T is 0.25. Start with your plan and replace it with your measurement after four cycles. How restock and top-up days sit in the price schedule is explained in how bin store pricing days work.

Step 3: find the usable share

Not every unit you buy reaches a bin. Some are broken, incomplete, unsafe, recalled or too big. The usable share S depends on the goods: shelf pulls and overstock run high; uninspected returns run lower. Before your first load, ask the supplier how the goods were graded and whether a manifest notes damage, and start with a cautious guess. Then replace it with your own count from each load: units that reached a bin divided by units received. Choosing goods that keep S high is covered in where bin stores get inventory.

Step 4: convert units to pallets and trucks

Units per pallet varies widely with the goods and how high the pallet is built. A pallet of phone cases and a pallet of small kitchen appliances can share a footprint and differ many times over in units. Ask the supplier for the count on a manifest, note the pallet height, and check both against your own counts.

Then think in trucks. A 53-ft dry van holds 26 standard 48 × 40 in pallets single-stacked, or more if the freight can be double-stacked safely. A 48-ft trailer holds 24. If your weekly pallet need is close to a trailer, a weekly truckload usually lowers freight per unit compared with several LTL shipments. If it is far below, buy pallets, or buy a truckload every two or three weeks and hold it, if you have the space and cash. Trailer and container capacities are set out in how many pallets fit in a trailer or container.

Worked example

Illustration only. B, U and T are round counts for one imaginary store. The usable share S and units per pallet P stay as letters, because they depend entirely on your goods and suppliers.

A store has 40 bins (B). A test bin holds 150 units (U). It restocks fully once a week (R = 1) and tops up a quarter fill mid-week (T = 0.25). It does not reuse leftovers (C = 0).

• Units needed on the floor: 40 × 150 × 1.25 = 7,500 units per week.
• Units to buy: 7,500 ÷ S.
• Pallets per week: 7,500 ÷ (S × P).

S × P is the number of usable units each pallet actually gives you, and it is the one figure that decides the answer. Compare the result with a trailer: a 53-ft van takes 26 pallets single-stacked, and 7,500 ÷ 26 is about 288. So if your pallets yield fewer than about 288 usable units each, this store needs more than a full trailer a week; if they yield double that, one trailer covers about two weeks.

Now see how sensitive the answer is. Pallets per week scale with 1 ÷ (S × P). If the usable share of your loads falls by a quarter, you need a third more pallets to fill the same bins. If you switch to goods that pack twice as many units per pallet, you need half the pallets. Small changes in U, S and P move the answer a lot, which is why you measure them instead of borrowing someone else's.

Buffer stock and storage

Weekly need is the minimum. You also need cover for a late truck. A simple rule:

Back-room pallet positions = pallets per cycle × (cycles of buffer + 1) + leftover area

With one cycle of buffer in the example, that is twice the weekly pallet count from the formula above, plus space for leftovers waiting for pickup. If you cannot store that much, you either buy more often in smaller loads, which usually costs more per unit, or accept a higher risk of thin bins.

Seasonal swings in weekly need

Your weekly need is not flat across the year. Crowds grow before the year-end holidays and around school and tax refund seasons in the US, and shrink in quiet months. Export-minded stores outside the US have their own calendars, such as Ramadan and Eid in Gulf markets or the school year in the southern hemisphere.

Plan in three steps:

1. Keep U fixed and change B or T. Add a few bins or an extra top-up in busy weeks rather than over-filling every bin.
2. Book busy-season loads early. Sellers and carriers get busy at the same time you do. Confirm extra trucks weeks ahead.
3. Cut volume before quiet months, not during them. If the formula says you need less, reduce the order before the slow month starts, or leftovers pile up for weeks.

Track the same five numbers below every week of the year. After one full year you will have your own seasonal curve, which beats any general rule.

Adjust after opening

Track these every cycle:

1. Units sold per day, by price day.
2. Units left at the end of the cycle.
3. Usable share of each load.
4. Units per pallet you actually received.
5. Whether bins looked full at opening and by mid-day on restock day.

If bins empty before the second price day, raise U or T. If leftovers grow each week, you are over-buying or the mix is wrong. If the usable share keeps falling, change suppliers or goods type.

Mistakes to avoid

• Using a supplier's units-per-pallet figure without checking it. Counts vary by builder and by load.
• Sizing on the opening week. The opening crowd is unusually large. Plan on normal weeks.
• Ignoring the usable share. Buying 7,500 units does not put 7,500 units in bins.
• No buffer. One late truck should not empty the store.
• Buying more than you can store. Pallets in the aisles are a safety risk and slow the restock.
• Forgetting the leftover pile. It takes storage space until it is picked up.

Next step

Once you know your weekly pallets, set alerts for matching loads. Members of Skyline Dealz Marketplace get first look at new pallets and truckloads; request access as a buyer and set lot size and region in your profile.