The number printed in the upper-right corner of a 501(c)(3) determination letter, labeled “DLN,” is a 14-digit Document Locator Number that the IRS uses to track the letter inside its own filing system. It is not a unique ID for your nonprofit, and it is almost never what someone actually needs when they ask for your “determination letter number.” What they usually want is either a copy of the determination letter itself or your Employer Identification Number (EIN).
What the DLN on Your Determination Letter Is
The Document Locator Number is a code the IRS assigns to every return, payment, or piece of correspondence that enters its Automated Data Processing system. It is not unique to nonprofits or to determination letters. Every Form 1040, every corporate return, and every letter the IRS mails out carries one. Its job is to help IRS staff pull a specific document out of their records, and that is essentially its only purpose.
The 14 digits encode processing information: which IRS campus handled the document, what type of document it is, the Julian date it was logged, and the year it was processed. None of that has any practical use for your organization. If your nonprofit received more than one letter from the IRS over the years, each would carry a different DLN. The letter itself may be the same document you rely on, but the number on it is disposable.
The Number You Probably Actually Need: Your EIN
The EIN is the number that matters for a nonprofit’s day-to-day operations. It is a nine-digit number the IRS assigns to identify your organization for all federal tax purposes, functioning much like a Social Security number does for an individual. You use it on every tax filing, every grant application, every bank account, and every donor acknowledgment. Unlike the DLN, the EIN stays with the organization for its entire life.
The IRS Tax Exempt Organization Search (TEOS) tool lets donors and grantmakers look up organizations by EIN or name. There is no way to look up a nonprofit by DLN, which is another sign of how little external weight that number carries. When a foundation or bank asks for your “IRS number,” the EIN is what they want.
What the Determination Letter Itself Contains
The determination letter is the document that actually proves your 501(c)(3) status. When the IRS approves an application for tax-exempt recognition, it mails a favorable determination letter that includes the organization’s legal name, its EIN, the section of the Internal Revenue Code under which it qualifies for exemption, the effective date of the exemption, the organization’s foundation classification (public charity or private foundation), and the DLN in the upper corner.
Donors, grantmakers, banks, and state agencies rely on this letter to confirm the organization is legitimately tax-exempt. When a foundation asks for your “IRS determination letter” on a grant application, they want a copy of this document. When a state tax office requires proof of federal exemption before granting a sales tax or property tax exemption, this letter is what you send. It is the single most important document your nonprofit possesses, and its value comes from the whole letter, not from any one number on it.
Why People Ask for the “Determination Letter Number”
Because the letter is such a common request, people often assume there must be a single number on it that identifies the organization to the IRS. There isn’t. Depending on who’s asking, the answer they need is one of three things:
- Your EIN, if they want to identify or verify your organization.
- A copy of the full determination letter, if they want documentary proof of exempt status.
- The DLN, only if the IRS itself has asked for it to locate a specific piece of correspondence.
The third case is rare. If a grantmaker, donor, or state agency is the one asking, it is almost certainly one of the first two.
Getting a Copy of the Determination Letter
Because the letter matters and the DLN doesn’t, the practical question most people are trying to answer is how to get a copy of the letter. The process depends on when the original was issued.
- For letters issued on or after January 1, 2014, download a copy directly from the IRS Tax Exempt Organization Search tool at no cost.
- For letters issued before 2014, submit Form 4506-B, Request for a Copy of Exempt Organization IRS Application or Letter, using the email address on the form. Allow at least 60 days for processing before following up. If more than 60 days pass, call IRS Customer Service at 877-829-5500.
You can also request an affirmation letter through Form 4506-B. An affirmation letter confirms your organization’s current tax-exempt status and serves the same purpose as the original determination letter for grantmakers and contributors. It is particularly useful when the original letter was issued under a former name or when a funder wants something more current.
If your organization is a subordinate under a group exemption, you won’t have an individual determination letter at all. Contact the central organization that holds the group exemption ruling to obtain confirmation of your status as a covered member.
Public Access to the Letter
Federal law requires every 501(c)(3) to make its exemption application and any related IRS correspondence, including the determination letter, available for public inspection. Under IRC Section 6104(d), the organization must allow anyone to inspect these documents at its principal office during regular business hours. Regional offices with three or more employees must also have copies available.
In-person requests must generally be filled the same day. Written requests must be fulfilled within 30 days. The organization can charge a reasonable fee for reproduction and postage but cannot charge for inspection itself. Failing to comply carries a penalty of $20 per day, and unlike the cap that applies to Form 990 disclosure failures, there is no maximum penalty for withholding the exemption application or determination letter.
Keeping the Letter Worth Anything
A determination letter is not permanent. Under IRC Section 6033(j), any organization that fails to file its required annual return or notice for three consecutive years automatically loses its tax-exempt status. The revocation takes effect on the filing due date of the third missed return. The IRS sends a notice after two missed years, but if the third filing is still missed, revocation happens automatically with no further warning.
Once revoked, the organization owes federal income tax on any income it receives and is no longer eligible for tax-deductible contributions. The IRS removes it from the public list of recognized exempt organizations. Getting reinstated requires filing a new application (Form 1023 or 1023-EZ), paying the user fee again, and potentially owing back taxes for the period between revocation and reinstatement.
The determination letter’s value is only as durable as your annual filings. Filing Form 990, 990-EZ, or 990-N every year is what keeps the letter, and the exemption behind it, in force. The DLN in the corner will never matter. The letter as a whole always will.