Public Support Test

The public support test is how the IRS decides whether your organization is a public charity or a private foundation — and that distinction is a big deal. Public charities get more favorable tax treatment, face less regulatory burden, and are far more attractive to donors and grantmakers.

There are two versions of the test, depending on your organization type. The first (under Section 509(a)(1) / 170(b)(1)(A)(vi)) requires that at least one-third of your total support comes from the general public — individual donations, government grants, and similar broad-based sources. Gifts from any single donor that exceed 2% of total support are generally capped at that 2% threshold for the calculation. The second test (under Section 509(a)(2)) is for organizations that earn significant revenue from activities related to their mission (like ticket sales or program fees). It requires that at least one-third of support comes from gifts, grants, and gross receipts from exempt activities, and no more than one-third comes from investment income and unrelated business income.

Both tests are calculated on a rolling five-year basis, which gives you some cushion — one bad fundraising year won't immediately knock you out of public charity status.

If you fail the public support test, the IRS reclassifies you as a private foundation. That means stricter rules on self-dealing, mandatory minimum distributions (5% of assets annually), excise taxes on investment income, and donors get lower deduction limits. Most small and mid-size nonprofits would find private foundation rules extremely burdensome.

Practically speaking, the public support test shapes your fundraising strategy. If you're too reliant on one or two major donors, you risk failing the test. Diversifying your funding base — even small donations from many individuals — strengthens your public charity status and your financial resilience.