Letter of intent (LOI)
Definition
A letter of intent (LOI) is a short document an applicant sends a funder before the full application to say they plan to apply, or to ask to be invited to apply. Depending on the funder, it is optional, required, or a competitive first round.
How it works
A letter of intent works differently by funder, so the first step is reading what the notice of funding opportunity or request for proposals asks for. There are three common types:
- Optional planning LOI. A brief letter with the PI's name, the project title, key personnel, and the participating institutions, used by the funder to plan review. It is not binding and not scored. NIH long used this model, but since December 2025 NIH no longer requests or accepts letters of intent.
- Required LOI (common at NSF). Some NSF solicitations require an LOI by a set date, and only applicants who submitted one may send a full proposal. Content is short, often a title, team, and synopsis.
- Competitive LOI or letter of inquiry (common at foundations). A 1 to 3 page summary of the project and budget that the funder screens. Only selected applicants are invited to submit a full proposal.
Why it matters for research offices
LOIs matter because their deadlines often come weeks or months before the full application, and missing a required one ends the opportunity. Research offices track LOI dates separately from final deadlines. For a limited submission, the internal competition may need to finish before the LOI date, not the full proposal date, which pulls the whole schedule earlier.
Letter of intent vs letter of support
A letter of intent goes from the applicant to the funder, while a letter of support goes from a collaborator or institution to the applicant, to be included in the application. NIH announced in July 2026 that letters of collaboration will replace letters of support, so check the current application instructions. The phrase "letter of intent" is also used for the signed statement a subaward partner provides committing to participate if funded, which is another reason to read the instructions carefully.
Common mistakes
- Treating a required LOI as optional and losing eligibility for the full proposal.
- Writing a foundation letter of inquiry like a planning notice, when it is actually the first competitive round.
- Changing the project substantially between a required LOI and the full proposal without checking the funder's rules.
- Missing the LOI deadline because only the final due date was on the calendar.
Frequently asked questions
No. Since December 2025, NIH no longer requests or accepts letters of intent, even when an older funding opportunity still mentions one. NSF and many foundations still use them.
Follow the funder's instructions first. A planning LOI lists the PI, title, key personnel, and institutions; a foundation letter of inquiry also summarizes the problem, approach, expected outcomes, and budget in 1 to 3 pages.
A letter of intent usually notifies a funder that you plan to apply. A letter of inquiry, common at foundations, asks the funder to invite you to submit a full proposal and is screened competitively.