Cost-to-serve is the total of everything you spend to serve a customer over a given period: picking and delivering their orders, but also entering them, correcting them, chasing the customer and handling their complaints. Subtracted from gross margin, it shows the real profitability of each account. Administrative costs often weigh more than expected, because they appear on no supplier invoice and vary widely from one customer to the next.
Why gross margin is not enough
Gross margin compares a selling price with a purchase price. It says nothing about the effort needed to actually earn that margin.
Take two customers of a plumbing supplies wholesaler, each buying the same amount over the year at the same margin rate. The first, a well-organised plumbing contractor, sends one consolidated order a week using your exact item codes. The second, a network of small branches, sends several orders a day, sometimes as a photo of a handwritten form, with its own item codes, and regularly calls to change a quantity or report a missing item.
In the margin report, these two customers look the same. In the day-to-day reality of your sales administration team and your warehouse, they are nothing alike. Cost-to-serve makes that difference visible.
What goes into the calculation
Costs can be grouped into three families.
- Logistics: picking (often proportional to the number of lines), packing, transport, urgent deliveries, returns.
- Sales: visits, time spent on quotes and tenders, discounts granted outside the price list.
- Administration: order entry, corrections and re-entry, follow-ups (missing information, unanswered quotes, late payments), dispute handling and credit notes.
You can go further (cost of credit, dedicated stock, payment terms), but these three families are enough for a useful first calculation.
How to calculate it simply
You do not need an activity-based costing system to get started. A five-step method in a spreadsheet already gives a reliable picture.
- Choose a period and a scope. A rolling year, and your top twenty or thirty customers to begin with.
- List the activities that consume time or money for each order: entry, correction, follow-up, dispute, picking, shipping.
- Give each activity a unit cost. For human tasks, multiply an average time by the fully loaded hourly cost of the person doing it. For logistics, start from your actual costs per line or per shipment.
- Count occurrences per customer: number of orders, lines, deliveries, follow-ups, disputes. Your ERP and inbox hold most of this data.
- Multiply, add up, compare. The total is the customer’s cost-to-serve. Subtracted from their gross margin, it gives their margin after cost-to-serve.
The principle fits on one line: for each activity, volume × time × hourly cost, then add everything up.
A worked example, entirely hypothetical
The figures below are made up to illustrate the calculation. Replace them with your own.
Imagine an industrial supplies distributor whose sales administrators have a fully loaded hourly cost of €36, or €0.60 per minute. It uses the following unit costs:
- entering an order: 10 minutes, so €6;
- correction or re-entry: 15 minutes, so €9;
- follow-up: 5 minutes, so €3;
- dispute (investigation, reply, credit note): 45 minutes, so €27;
- picking: €1 per line;
- shipping: €15 per delivery.
Its two customers each generate €120,000 in revenue over the year, with €30,000 in gross margin.
Customer A: 48 orders of 10 lines, 2 corrections, 4 follow-ups, 2 disputes.
- Administration: €288 entry + €18 corrections + €12 follow-ups + €54 disputes = €372
- Logistics: €480 picking + €720 shipping = €1,200
- Cost-to-serve: €1,572, margin after cost-to-serve: €28,428
Customer B: 400 orders of 3 lines, 40 corrections, 30 follow-ups, 20 disputes.
- Administration: €2,400 entry + €360 corrections + €90 follow-ups + €540 disputes = €3,390
- Logistics: €1,200 picking + €6,000 shipping = €7,200
- Cost-to-serve: €10,590, margin after cost-to-serve: €19,410
With identical revenue and gross margin, customer B costs almost seven times as much to serve. Its administrative workload is nine times that of customer A, and accounts for a third of its cost-to-serve.
The weight of administrative costs
In this example, logistics is still the largest item. But administrative costs deserve particular attention, for three reasons.
They are invisible. Transport comes with an invoice, and picking is measured in the warehouse. The quarter of an hour spent deciphering a scanned order or calling a customer back about an unknown item code shows up nowhere. It disappears into the sales admin payroll.
They depend on customer habits more than on volumes. A customer who orders in a clean format, using your item codes, costs little to enter. A customer who sends a different PDF every time, with their own item codes and units that do not match your pack sizes, generates corrections and follow-ups. On this topic, see our article on matching customer references to your catalogue.
They cascade. An entry error leads to a wrong delivery, which leads to a dispute, a credit note, sometimes a return and a reshipment. The cost of a badly entered line goes far beyond the time it took to enter it. For a detailed estimate, see the true cost of manual order entry.
What to do with the results
The goal is not to drop your most expensive customers, but to know where to act.
- On logistics: minimum order values, free-shipping thresholds, small-order fees, grouped deliveries.
- On sales: factor cost-to-serve into price and discount negotiations.
- On administration: lower the unit cost of each task rather than asking the customer to change their habits.
This last lever is where automation has a direct effect. Eledone reads purchase orders received by email, whatever their format, finds the items and checks prices, stock and credit limits before entering the order into the ERP. Anything out of the ordinary (an unusual price, an ambiguous item, an exceeded credit limit) is flagged to the team. The entry cost of a customer like B goes down, and so do the corrections: among our customers, entry-related disputes fall by 30%. The customer keeps ordering as before, but costs less to serve.
Pitfalls to avoid
- Aiming for precision before you have a first estimate. A rough calculation on twenty customers beats a perfect model that is never finished.
- Guessing the times. Time a few days of work, or use the timestamps in your ERP and inbox.
- Doing the calculation once. Customer habits change; redo it every year, or after an organisational change.
Frequently asked questions
What is the difference between cost-to-serve and net margin?
Net margin is calculated for the company as a whole. Cost-to-serve is calculated customer by customer, or channel by channel, and is used to compare the profitability of accounts with one another.
Do you need software to calculate cost-to-serve?
Not to get started. A spreadsheet, volumes extracted from the ERP and a few measured times are enough. A dedicated tool becomes useful if you want to track the indicator continuously across hundreds of customers.
Which customers should you analyse first?
Your largest accounts, and the ones your sales admin team spontaneously describes as “difficult”. They are often the ones with the biggest surprises.
How can you reduce cost-to-serve without harming the customer relationship?
Start with your own internal costs, especially administrative ones, before changing the customer’s terms. You can try Eledone for free on one of your orders to see what automated order entry looks like.
Want to see what it looks like on orders from your most expensive customers to serve?
Book a demo