How to use the customer revenue concentration calculator
Enter annual revenue for each customer and the calculator shows what share of total revenue your largest accounts represent. If the top three customers account for more than 60% of revenue, losing a single contract renewal can move the whole year, so this is one of the first numbers to check before planning sales capacity.
The math is straightforward. Amounts are sorted from largest to smallest, the top N are added together, and that subtotal is divided by the total of every amount entered. If you pick a larger N than the number of customers you entered, only the customers actually entered are counted and the result label says so. The table lists each customer with its own share and the running cumulative share.
This tool works from individual customer amounts. If you would rather score how evenly revenue is spread across channels or product lines, use the revenue diversification (concentration risk) calculator instead.
Frequently asked questions
There is no single threshold, because it depends on your industry and contract lengths. As a working rule, a single customer above 30% or a top three above 70% means each renewal date carries real revenue risk, so it is worth building a pipeline of replacement accounts.
Yes. The math is identical as long as every row uses the same measure. If margins vary a lot between accounts, profit-based concentration often reflects the real exposure better than revenue does.