Warehouse stock management for a service company: minimum, maximum and counting

Where it goes wrong in the warehouse

The central warehouse of a service company holds parts, materials and consumables, often hundreds of items. What usually goes wrong:

• The same part under three names. Nobody knows how many there really are.
• No fixed location. Only the person who put a part away can find it.
• Ordering by eye. An order goes out when the box looks empty, and that is often too late.
• Taking without noting. A technician quickly grabs something in the morning, and the count no longer adds up.
• Counting once a year. By then, the differences are so old that nobody can explain them.

You see the result outside the warehouse: a technician standing empty-handed at the customer’s, or a second trip for one part.

The basics: one reference and one location per item

1. One item, one reference. Choose a fixed way of naming, for example type, size and material: “Ball valve 1/2 brass”. Add the supplier’s reference, and possibly a barcode.
2. A unit that makes sense. Count in the same unit as you use: pieces, metres or boxes.
3. A fixed location with a code. A code per rack, level and bin, such as A-05-1, on the rack and in your list.
4. Frequently used parts close to the exit. Heavy parts low down, rarely used ones at the back or at the top.
5. Goods and services kept apart. Labour and fixed-price items have no stock and do not belong in your counts.
6. A decision on dead stock. Parts for units you no longer maintain, you send back, sell or write off, in consultation with your accountant.

A minimum and a maximum per item

The minimum is the level at which you replenish: if the stock falls below it, you order. The maximum is the quantity you end up with after an order.

A common rule of thumb for calculating the minimum stock, which logistics also calls the reorder point:

Minimum = average consumption per day × supplier’s lead time in days + safety stock

The safety stock absorbs whatever deviates from normal consumption, such as a busy week or a late delivery. A simple way is to take the consumption of a few extra days. The maximum is the minimum plus the quantity you want to order at once, for example a month’s consumption.

A worked example for one item, with values to adapt:

That rule of thumb is a starting point. Fine-tune it with these rules:

• Choose a representative period. Heating parts go faster in winter than in summer. Recalculate before the season starts.
• Also count what goes to the vans. The warehouse’s consumption is everything that leaves it.
• Give expensive parts that are rarely used a low minimum. A specific circuit board is better ordered for a specific intervention.
• Review a minimum after every shortage, and whenever a supplier changes its lead time.
• Start with the items that move most often.

Counting: a few items often, or everything once a year?

The two do not exclude each other. If you spread the counting, count most often what moves a lot or costs a lot. A few rules for every count:

• Count a bin when nothing is in transit, so without a transfer that has been prepared but not yet confirmed.
• Give every difference a reason: damaged, lost, found or return not recorded. The reason tells you where the circuit leaks.
• For a large difference, count again before you correct.

For the accounts, every company that is required to keep accounts carries out, at least once a year, the stocktaking needed for an inventory (article III.89 of the Code of Economic Law, Wetboek van economisch recht / Code de droit économique, checked on 30 October 2026). Discuss with your accountant how to count and value the stock for this.

Transfers to the vans

A large part of what leaves the warehouse goes to the vans. There too, a single circuit works best: a request, an approval, then the warehouse prepares and confirms the transfer. Prepare at a fixed time, for example in the afternoon for the next day’s interventions, and do not let technicians take from the racks themselves. How to keep the van itself stocked is covered in van stock for technicians.

What else slows down work in the warehouse:

• frequently used parts at the back, and heavy ones at the top;
• overfull bins, where one box disappears behind another;
• deliveries that stay in the corridor until someone has time;
• preparing at the last minute, while the technician waits.

Stock management in Excel: how far does it go?

An Excel list with the reference, location, minimum and stock works in a small warehouse where one person does all the taking out and replenishing. It falls behind as soon as several people take from the warehouse, the vans have their own stock or you want to know which parts were used per intervention.

An example: a heating company’s warehouse

A heating company with a handful of technicians has a warehouse behind the office. The storekeeper gives each bin a code and puts the pumps, valves and gaskets used most often in the rack next to the door. For the items that move most, the storekeeper calculates a minimum and a maximum from last month’s consumption and the wholesaler’s lead time, and recalculates them before the heating season.

Every Friday, the storekeeper counts a few bins and notes the reason for every difference. Technicians request their parts, and the storekeeper prepares them the afternoon before, per van. At the end of the financial year, everything is counted once, as agreed with the accountant.

How it works in Digitalnatie Service Suite

The warehouse is in the parts menu. It is the central stock, and each van also has its own stock.

• The items: four figures filter the list with one click. They count all items, the items below the minimum, those out of stock in the warehouse and those in stock in a van. The columns show the available stock, the minimum and maximum, the coverage in days based on the consumption over the last 30 days, and that consumption. A filter shows the items to order.
• Replenishment rules: on the item record, you set a minimum and a maximum per storage location in the warehouse. Below the minimum, Service Suite itself creates a replenishment or a purchase request up to the maximum. The van minimums are set in the van stock.
• Locations and the plan: search for a part, and the structure view shows the path to the bin. Once the plan has been drawn, the 2D/3D view shows where a part is, also in the vans.
• Reorganising spots overfull storage locations, frequently used parts far from the exit, heavy parts stored high up and parts that should be in the vans. A proposal never moves stock.
• Counting: on the item record, recording a count covers the main location, and a bin is counted separately. The difference is recorded as a stock correction. In a van, correcting a count always requires a reason.
• Transfers: an approved request becomes a van replenishment transfer. The warehouse prepares it and validates it; only then does the stock leave the warehouse. The movements tab shows every receipt and issue.
• Who sees what: the administrator and the Warehouse Manager manage the whole warehouse, including the items, the replenishment rules and the counts. The manager and the Warehouse Employee also process transfers. The planner only sees the locations and the plan. Accounting and sales have no access to the warehouse.

Categories, storage locations and vans are created in the stock and parts configuration. You import your items and your opening stock from an Excel or CSV file in the data import screen: see importing customer data.

Good to know:

• Enabling storage locations in the company rules is permanent: you cannot switch them off again from the application.
• Lots and serial numbers are not entered in the application. Such a transfer or count is completed outside the application: ask Digitalnatie.
• A validated transfer cannot be undone in the application, and there is no transfer from one van to another.
• To create a new warehouse, ask Digitalnatie.

More about the module on the stock and parts page. How the right parts prevent a second visit is covered in first-time fix rate, and you follow up the most used parts in your KPIs.

Frequently asked questions

How do you calculate the minimum stock of an item?

A common rule of thumb is the average consumption per day times the supplier’s lead time in days, plus a safety stock for a busy period or a late delivery. Take the consumption over a representative period and adjust the minimum after every shortage. The rule of thumb is a starting point, not a fixed standard.

What is the difference between minimum stock and safety stock?

The safety stock is the buffer for whatever deviates from normal consumption. The minimum, or reorder point, is the level at which you replenish: the consumption during the lead time plus that buffer. If the stock falls below the minimum, you order up to the maximum.

How often should you count the stock in the warehouse?

Count a few items or bins every week, and most often the parts that move a lot or cost a lot. That way, a difference surfaces while someone can still explain it. For the accounts, you also take an inventory at least once a year; discuss with your accountant how to count and value that stock.

What does Service Suite do when an item falls below its minimum?

The item appears among the items below the minimum. With a replenishment rule on the item record, Service Suite itself creates a replenishment or a purchase request up to the maximum. The van minimums are set separately, in the van stock.