Customer profitability analysis for distributors

Ask a supply house owner to name their best customers and most will list their biggest accounts by sales. That's a reasonable guess, and it's often wrong. Sales tell you who buys the most. They don't tell you who makes you money.

A customer profitability analysis answers that second question. This guide explains why the two lists differ, how to run a simple version from your own data, and what to do once you have it.

Why your biggest customers aren't always your most profitable

Profit on an account depends on three things: what they buy, what you charge, and what it costs you to serve them. Most distributors track the first two closely and estimate the third loosely, if at all.

Cost to serve is where the surprises are. Every order has to be entered, picked, packed, delivered and invoiced, and those costs don't shrink much when the order does.

Randy MacLean of WayPoint Analytics described one example in June. A distributor's invoice brought in over $1,000 and netted $12.87 in operating profit. A follow-up order with five low-value lines lost $76.67. Together, the customer cost the distributor $63.79. Shipped as one order, the same items would have made $55.09 (ASA).

Distribution consultant Al Bates has made the same point at the customer level. In his example of how profit typically spreads across a distributor's customers, 15% of customers produce 100% of the profit, and about a third lose money, mainly because they place too many small orders (Distribution Strategy Group).

Why it matters more right now

Large distributors are growing fast, but not always at better margins. Graybar's third quarter 2026 sales rose 22%, while its gross margin slipped from about 19.4% of sales to 18.9% (Graybar 10-Q). A company that size can absorb that with scale. A $20 million supply house has less room, so knowing which accounts carry the business matters more.

The three numbers that make up customer profitability

1. Gross profit by customer

Sales minus cost of goods, for each account, over the last 12 months. Most systems can report this directly. It's the starting point, not the answer.

2. Cost to serve by customer

An estimate of what it costs you to handle that customer's business. The simplest version uses three drivers:

• Orders: cost to enter and invoice each order.
• Lines: cost to pick each line.
• Deliveries: cost of each truck stop, or counter pickups at a lower rate.

3. Net profit by customer

Gross profit minus cost to serve. This is the number that sorts customers into the ones carrying you and the ones you're carrying.

How to run a customer profitability analysis

1. Export 12 months of invoice detail from Prophet 21, Eclipse or QuickBooks: customer, invoice number, line count, sales and cost.
2. Total gross profit by customer. Sum sales minus cost for each account.
3. Count activity by customer. Number of orders, number of lines and number of deliveries.
4. Estimate your unit costs. Take last year's warehouse, delivery and order entry costs and divide each by its activity count. A rough number is fine to start.
5. Calculate cost to serve. Multiply each customer's activity by your unit costs and add it up.
6. Subtract and sort. Net profit equals gross profit minus cost to serve. Sort from highest to lowest and split into four groups: high profit, good profit, some profit and unprofitable.
7. Look at your top 50 by sales. Find where each one lands. The accounts that are big on sales but low on net profit are where the work starts.

What to do with unprofitable customers

Losing money on an account doesn't mean you should drop it. Most of the time the fix is in how they buy, not whether they buy.

• Change the order pattern. Suggest a regular weekly order instead of several small ones, or set a minimum for free delivery.
• Review pricing. Check whether the account's price level still makes sense for what you deliver.
• Move small orders to the counter or online. Lower cost to serve without losing the sale.
• Grow the share. Some small accounts are small with you, not small overall. Contractors often split their buying across several suppliers, and more lines per order can turn an unprofitable account profitable.

Then watch the profitable ones closely. If 15% of customers carry the business, a change in how any of them orders is worth noticing within days, not at the end of the year.

Frequently asked questions

How often should a distributor run a customer profitability analysis? Once a year in full is a good start, with a quarterly check on your top accounts. The goal is to spot accounts whose profit is changing before it shows up in the year end numbers.

What is cost to serve in distribution? Cost to serve is what it costs a distributor to handle a customer's business beyond the product itself: taking orders, picking lines, delivering and invoicing. Customers with many small orders usually cost more to serve per dollar of sales.

Should I stop selling to unprofitable customers? Usually not. Most unprofitable accounts can be fixed by changing how they order, adjusting pricing or growing your share of their business. A small number may never be profitable, and those are worth a direct conversation.