How the sales funnel calculation works
Each stage equals the preceding stage multiplied by its conversion rate. With 10,000 visitors, rates of 5%, 30%, 20%, and 25% yield 500 leads, 150 qualified leads, 30 opportunities, and 7.5 expected customers. At an average deal value of $5,000, that is $37,500 in expected revenue. The 7.5 is an average planning value across comparable months, not a literal customer count.
Use consistent stage definitions
Define a visitor, lead, qualified lead, opportunity, and customer in your own analytics and CRM before using historical rates. Count unique people or organizations consistently, and avoid combining stages from different cohorts or time periods without explaining the lag between them. A lead generated this month may close in a later month, so a same-month multiplication is a simplified model.
Stress-test assumptions
Try several rate and deal-value scenarios rather than presenting one point estimate as a commitment. Check whether lead quality changes as traffic grows and whether the sales team can handle the modeled volume. Deal value should use the same revenue definition for all customers; exclude costs if you are calling the output revenue, then assess margin and acquisition cost separately.