How concentrated is my revenue?
If one client leaves and it breaks your business, that's not a sales problem. That's a concentration problem. Here's how to measure it and know whether your revenue base is fragile or resilient.
The short answer
Revenue concentration measures how much of your income depends on a small number of customers. If your top customer is 35% of revenue, losing them would be catastrophic. If your top 10 customers represent 90%, you're running a business that depends on personal relationships, not a scalable operation. The math is simple: each customer's revenue divided by total revenue.
Why revenue concentration is the risk nobody talks about
A $500K business with 200 customers is fundamentally different from a $500K business with 5 customers. They report the same revenue but carry completely different risk profiles.
Concentration risk builds quietly. You land a big client. They grow. You hire to serve them. They become 30%, then 40% of revenue. Every quarter you're more dependent, more exposed. Then they switch vendors, get acquired, or change direction, and you're left with a cost structure built for revenue that no longer exists.
Banks and lenders check for concentration risk. Acquirers discount for it. Insurance underwriters flag it. If the people evaluating your business care about this number, you should too.
How to measure revenue concentration and what the thresholds mean
The calculation is straightforward: divide each customer's revenue by your total revenue. The risk thresholds used by most analysts:
These are guidelines, not absolutes. A 30% top customer is fine if they're under a multi-year contract. The same 30% from a month-to-month client is a very different situation.
How to check revenue concentration in QuickBooks Online
- 1Go to Reports → Sales by Customer Summary
Set the date range to the last 12 months (or the current quarter). Click Run report.
- 2Sort by amount descending
Click the Total column header to sort from highest to lowest. Your biggest customers are now at the top.
- 3Note the grand total at the bottom
This is your total revenue for the period.
- 4Calculate percentages for your top customers
Divide your #1 customer's revenue by total revenue. Then sum your top 5 and divide by total. Then top 10. These three percentages are your concentration profile.
Total time: 10-15 minutes. This is one of the easier metrics to pull from QuickBooks. The Sales by Customer Summary report does most of the work for you.
How to check revenue concentration in Xero
- 1Go to Business → Invoices
Filter by the last 12 months. Export the invoice list to CSV.
- 2Build a customer revenue summary in a spreadsheet
Use a pivot table with customer name as the row and invoice total as the value. Sort descending.
- 3Calculate concentration percentages
Same math: top 1, top 5, top 10 as a percentage of total. Xero doesn't have a built-in Sales by Customer Summary like QuickBooks, so the pivot table step is necessary.
Total time: 15-20 minutes. The extra spreadsheet work for Xero adds about 5 minutes compared to QuickBooks.
What it takes to monitor concentration over time
- 10-20 minutes monthly. One of the quicker metrics, but it still requires a manual export and calculation each month.
- A snapshot is not enough. Knowing your concentration today is useful, but the trend matters more. Is it getting better or worse? That requires tracking the same metric month after month.
- The risk is not just the percentage. A 25% top customer with a long-term contract is different from a 25% top customer on month-to-month terms. Concentration context requires CRM data that your accounting software does not have.
Or monitor revenue concentration automatically
Bottomline calculates your concentration profile every month, tracks it over time, and flags changes so you can see whether your revenue base is becoming more or less resilient.
The trend context is what makes this actionable. Knowing your top customer is 22% of revenue is a data point. Knowing it was 26% three months ago tells you your diversification efforts are working.