You may use the conventional partnership buyout calculation to estimate the value of your partner's share in the business. A buyout agreement lets you plan what'll happen when a partner leaves the business.What should be included in a buyout agreement? Buying out a business partner can be done in several ways. This guide will walk you through the essential steps and considerations for executing a successful business partner buyout. It's not a calculation, it's a negotiation. Verbal agreements can be enforced, but it requires some kind of corroborating evidence (like email) or testimony. Buyout Agreement: A legal document that outlines the terms and conditions of a transaction in which one party purchases a stake in a business from the other.