What's the difference between The Business Case and The Project Charter?

Business case is a sales pitch or a funding request for the project to the management or investment board. A project charter, on the other hand is a formal documentation of how a project will be managed, list of initial assumptions, risk, issues, scope, high level timeline etc.

A business case is often a pre-cursor to developing a project charter

Business Case is an analysis of the organizational value, feasibility, costs, benefits, and risks of the project plan.

The purpose of a project charter is to define the focus, scope, direction, and motivation for a team. The project champion typically creates the preliminary charter with the team leader. The project team reviews the draft and provides input for the champion’s final approval. 

PMI’s PMBOK recommends the use of a Project Charter as the project initiation document. The “project initiator” or Project Sponsor is external to the project organization and at a level that is able to fund the project. The development and issuance of the Project Charter by the project initiator links the project to the ongoing work of the organization.

A Business Case justifies the need to undertake the project. A Project Charter gives formal authority to the Project Manager to undertake the project.

The subtle difference in my mind is that the first is a sales pitch to investors or management whereas the second forms part of the formal project documentation.

I agree with the expert answers.

I agreed with the team for what they said about the difference.