How to Estimate a B2B Customer's Purchase Potential

Purchase potential is how much a customer would buy from you each month if they bought everything they consume in your category. It is the number that separates deliberate prioritization from effort spread in the dark — and in a business that sells on terms, it also sizes the credit limit.

Why estimate potential

• Prioritizes the calendar by return rather than by familiarity
• Identifies underserved accounts: buying little, could buy a lot
• Sizes a limit that matches real need, avoiding idle exposure
• Reveals concentration before it shows up in receivables

Method 1: percentage of revenue

The most direct route when a reliable revenue estimate exists.

Potential = customer monthly revenue × typical share spent in your category

A bakery chain doing $500,000 a month that spends about 6% on packaging has $30,000 a month of potential in that category. The percentage comes from your own history: across customers whose revenue you know, calculate what each spends with you.

Method 2: operational proxy

When revenue data is unreliable, use a physical indicator of the customer's operation:

A proxy is often more reliable than reported revenue, because it is observable and hard to inflate.

Method 3: comparable accounts

Compare the prospect to active customers with an equivalent profile — same industry, size and region — and use their average purchase as the estimate.

This is the most accurate method once you have a mature book, because it embeds the real behavior of your category for that profile. All it requires is a consistently classified customer base.

From potential to share of wallet

With potential estimated, calculate the share you already hold:

Share = current purchases ÷ estimated potential

• Below 20% — underserved account, clear expansion opportunity
• 20% to 60% — established relationship, competing with others
• Above 60% — mature account; growth requires a new category

That number changes the sales conversation: it is no longer "how much do you want to buy," it is "you consume X and buy Y from us."

How potential feeds the credit decision

A limit disconnected from potential creates two opposite problems. A limit far above need sits idle, yet still counts as committed exposure and eats portfolio capacity. A limit below potential blocks good sales and pushes the customer to a competitor exactly when they buy most.

The correct reading crosses potential with ability to pay: potential says how much they would buy; underwriting says how much they can carry. The limit comes from the lower of the two — using the methods in how to set a credit limit.

Estimation mistakes

• Using reported revenue with no verification. Overstates potential and inflates the limit.
• Ignoring seasonality. An average hides the peaks that stall orders in high season.
• Treating a group as a single location. A 12-store chain has aggregate potential and aggregate exposure.
• Never revisiting. Potential changes with the customer's operation; refresh it at least annually.

What to take from this

Estimate potential from observable data, calculate your share, and use the number on both ends: to prioritize commercial effort and to size the limit. Limits and potential that drift apart produce either blocked sales or idle exposure.