The cover letter included with a full proposal is meant to be brief. It provides a concise summary of the proposal itself. It’s important to know that in some cases the foundation staff will remove the cover letter and any proposal attachments before the review of applications begins. So you should never include any critical information – such as the amount your are requesting or something essential to the project – in the cover letter only. You can, on the other hand, duplicate a few sentences that are contained in the proposal.
If you have any relationship with a foundation program officer or board member you should mention it in your opening paragraph along with a straightforward statement about why your project is a strong match with the vision and priorities of the grantmaker. If you happen to be applying for a grant from a private company be sure to include the number of employees who volunteer with you or if one of the company’s executives is part of your board of directors.
In the next paragraph briefly describe the project and the amount of funding you are requesting. Your statement should make it easy for a program officer to use it in internal materials created to summarize all applicant proposals.
In the third paragraph you should convey how passionate your organization is about the project. Foundations like to see other funding so also include other resources and how they will enhance the grant. Other comments should depend on the research you have done on this funder. You might invite them for a visit to your site or propose that you contact them in a couple weeks to get an update. Also be sure to provide the appropriate contact information for the person with whom they should communicate about the proposal. That may well be a different person from the executives or board member signing the letter.
If you have intimate knowledge of the funder and know that they like an emotional appeal you might include an appropriate story in the cover letter. But in general it is best at this point to leave the letter fairly formal.