What Is the 33 Percent Rule for Nonprofits?
By Katie Wilson
July 11, 2025
The “33 percent rule” is the IRS public support test that keeps most 501(c)(3) organizations classified as public charities rather than private foundations. Passing the test means that at least one-third (33 ⅓ percent) of a nonprofit’s total support over a rolling five-year period must come from the public or from mission-related program revenue. Failing it can trigger costly reclassification, excise taxes, and tighter restrictions on your fundraising and grant-making. This article explains what counts as public support, how to calculate the ratio, and practical steps to stay in compliance—so your organization can focus on its mission instead of tax headaches.
| Public-charity pathway | What counts toward the 33 %? | Extra limitations |
|---|---|---|
| 509(a)(1) / 170(b)(1)(A)(vi) | Donations from individuals, corporations, other public charities, government entities; each donor’s amount above 2 % of total support is capped at 2 % for the numerator | None |
| 509(a)(2) | Everything above plus program-service revenue (ticket sales, membership fees, etc.) | No more than one-third of total support may come from investment income or unrelated business income |
How to Calculate Your Public Support Percentage
- Pick the measuring period – the current tax year plus the four immediately preceding years.
- Add “public support” – qualifying contributions and, for 509(a)(2), program revenue.
- Add “total support” – public support + all other revenue, including large gifts and investment income.
- Divide public support by total support.
- Result ≥ 33 ⅓ %? You pass. Otherwise, you may still qualify under the 10 percent facts-and-circumstances test, but that requires extra IRS scrutiny.
Why is the 33% Rule Important?
Compliance with the 33% rule is not just about following IRS regulations; it’s about building and maintaining a healthy, sustainable organization.
- Maintaining Public Charity Status: This is the most direct and critical reason. Failing the public support test can lead to an organization being reclassified as a private foundation, which comes with more stringent regulations and less favorable tax-deductibility for donors.
- Donor Confidence and Trust: A broad base of support is a strong indicator of a nonprofit’s credibility and the value of its mission. When donors see that an organization is supported by a wide range of individuals and groups, it builds confidence that their contributions are going to a well-regarded and effective cause.
What Happens if a Nonprofit Fails the Test?
Failing to meet the 33% threshold does not automatically mean an organization will lose its public charity status. The IRS provides some flexibility.
- The “Facts and Circumstances” Test: If a nonprofit’s public support is at least 10% of its total support, it may still qualify as a public charity under the “facts and circumstances” test. This requires the organization to demonstrate that it is actively working to attract new public support and has a representative governing body.
- Reclassification as a Private Foundation: If a nonprofit’s public support falls below 10%, or it fails the “facts and circumstances” test, it will likely be reclassified as a private foundation. This can have significant consequences, including limitations on donor tax deductions and increased administrative burdens.
Frequently Asked Questions (FAQ)
Q: How is the public support test calculated?
A: The public support test is calculated over a five-year period (the current year and the four preceding years). It compares the amount of public support to the organization’s total support.
Q: What is considered “public support”?
A: Public support includes contributions from the general public (individuals and corporations), government grants, and grants from other public charities. For the 509(a)(1) test, large individual donations are limited to 2% of the organization’s total support. For the 509(a)(2) test, revenue from activities related to the organization’s exempt purpose also counts as public support.
Q: What is the difference between a public charity and a private foundation?
A: A public charity is broadly supported by the public and receives more favorable tax treatment. A private foundation is typically controlled and supported by a small number of donors and is subject to more stringent operating rules and regulations.
Q: Can a nonprofit switch between the 509(a)(1) and 509(a)(2) tests?
A: Yes, a nonprofit can switch between the two tests from year to year to use the one that best reflects its sources of support.
Q: What should a new nonprofit do to ensure it meets the public support test?
A: New nonprofits are not required to meet the public support test until their sixth year of operation. However, it is crucial to start building a broad base of support from the beginning. This includes developing a diverse fundraising strategy and actively engaging with the community.
