Customer Concentration Calculator
Customer concentration measures how much of your revenue depends on a small number of customers. The more revenue a single customer or a tight group of top customers represents, the more exposed you are if one of them leaves. The U.S. Securities and Exchange Commission treats a customer at 10% or more of revenue as material enough to disclose. Enter total revenue, your largest customer's revenue, and your combined top-customers revenue. This calculator returns top-customer and top-group concentration shares as percentages.
Customer concentration formula
Top customer concentration = (largest customer revenue / total revenue) * 100
Top group concentration = (combined top revenue / total revenue) * 100
Remaining share = 100 - top group concentration
Each concentration is a revenue share over total revenue. The remaining share is what is spread across all other customers, a rough diversification gauge.
Reading concentration risk
- The SEC requires disclosure when one customer is 10% or more of revenue.
- Higher concentration means larger revenue loss if a top customer leaves.
- Compare top-customer and top-group shares to see single-point versus clustered risk.
- A large remaining share signals a more diversified, resilient base.
- Use consistent revenue figures (same period, same recognition basis) for all inputs.
Customer concentration: frequently asked questions
What is customer concentration?
Customer concentration is the share of total revenue that comes from your largest customer or a small group of top customers. High concentration means a few customers drive most revenue, which raises the risk if any of them leaves.
How do I calculate customer concentration?
Divide the revenue from a single customer (or the combined revenue of your top customers) by total revenue, then multiply by 100. For example, a top customer contributing US$300,000 of US$1,000,000 total is 30% concentration.
Why does customer concentration matter?
It is a risk measure. The U.S. Securities and Exchange Commission requires public companies to disclose when a single customer accounts for 10% or more of revenue, because losing such a customer could materially affect the business.
What concentration level is risky?
There is no universal threshold, but the SEC 10% disclosure rule signals that a single customer at or above 10% of revenue is material. The higher the share from one or a few customers, the greater the revenue risk if they leave.
How does top-customer share differ from top-group share?
Top-customer share is the single largest customer over total revenue. Top-group share combines the revenue of your several largest customers. This calculator reports both so you can see single-point and clustered concentration risk.
Official sources
- U.S. Securities and Exchange Commission: EDGAR company filings (customer concentration disclosures).
- U.S. Securities and Exchange Commission: Guidance on Management's Discussion and Analysis.
Reviewed by the CalculatorHub team, edited by James Graham, 16 June 2026. See our methodology.