Professional Selling Skills Training: Is there a formula people can use to determine how big their sales pipeline needs to be? Your pipeline should always contain as many contacts as it takes to replace all of your business during the current sales cycle. For example, if you’re currently doing business with 25 customers and it takes six months to close a sale, then you would need to either have at least 50 prospects in your pipeline or enough prospects that would bring in the same amount of business to replace your existing business. Additionally, a quick rule of thumb is if your sales process takes more than six months, you need to add the number you need by the number of months above six times your base number. So, for a nine month sales cycle, take the base number of prospects you need (for example: 50) and add another 30% (9 months – 6 months = 3 months). In this case, you would add another 15 prospects.