Run the 5-year test before filing Form 990 to catch a shortfall early.
Nonprofit
IRS public support test calculator that tells you pass or fail in seconds.
Run the 509(a)(1) or 509(a)(2) public support test with 5 years of data to see if your nonprofit passes the 33.33% threshold.
Direct answerThis tool calculates the 5-year public support percentage for 509(a)(1) or 509(a)(2) organizations, compares it to the 33.33% threshold, and shows safety margin and trend.
509(a)(1) and (a)(2)5-year testBuilt for nonprofits
1. Enter support data
CalculatorEnter the test type, 5 years of total and public support, and any unusual grant exclusion. Or load the sample scenario.
Enter assumptions or load a sample scenario to see the results.
Live Tool
IRS Public Support Test Calculator in the browser
The functional tool stays first: enter your support data, review the result, and only then scroll into the guide below.
Privacy-first workflow
This page runs in the browser and does not upload any data.
What this tool is built to solve
This tool calculates the 5-year public support percentage for 509(a)(1) or 509(a)(2) organizations, compares it to the 33.33% threshold, and shows safety margin and trend.
Validate the public support percentage before completing Part II or Part III.
Track the trend so the board can adjust fundraising strategy before a failure occurs.
Key signals
The result cards explain where the public support percentage stands relative to the threshold.
Decision support
Use these cards to move from the test result into the next compliance or fundraising discussion.
Detailed breakdown
The breakdown keeps the math explainable and export-ready.
Aggregate five years of support data into a single public support percentage using the IRS rolling method.
See the pass/fail result and how far above or below the 33.33% threshold your organization falls.
Exclude unusual grants that could distort the support ratio under the IRS unusual grant rule.
Track how the public support percentage moves year over year to catch classification risk early.
Guide Below The Tool
How to use the IRS public support test calculator well
This section is written for searchers, answer engines, and busy nonprofit teams: direct definitions, practical steps, and concrete follow-up guidance.
A public support test calculator computes the 5-year public support percentage for 509(a)(1) or 509(a)(2) organizations and compares it against the 33.33% mechanical threshold.
Tax-exempt organizations, CPAs preparing Form 990 Schedule A, and board treasurers monitoring classification risk.
Public support sources, unusual grants that distort the ratio, and the direction of the trend over the 5-year window.
Workflow
Four practical steps
Use the tool as a fast decision layer. The goal is to confirm public charity status or flag risk before the next Form 990 filing.
1
Select 509(a)(1) or (a)(2).Choose the test that matches your organization's primary source of public support.
2
Enter 5 years of total and public support.Add total support and public support amounts for each of the five most recent tax years.
3
Exclude unusual grants if applicable.Enter any amounts that qualify for exclusion under the unusual grant rule to avoid distortion.
4
Review pass/fail, safety margin, and trend.Check whether the organization passes, how much margin exists, and whether the trend is improving or declining.
Review Checklist
What reviewers usually validate first
These are the areas teams usually discuss first once the public support test result is visible.
Confirm which receipts qualify as public support under the applicable section and exclude disqualified person contributions.
For 509(a)(1), verify that contributions from any single donor are limited to the greater of 2% of total support or $5,000.
Document why any excluded grant qualifies as unusual and retain the analysis for audit support.
Confirm that investment income is included in total support but not in public support for 509(a)(1) organizations.
Verify whether membership dues qualify as public support or must be excluded based on the benefits provided.
Track the year-over-year direction of the public support percentage to catch downward trends before they trigger reclassification.
Why This Page Exists
Built to close the gap between a tax rule and a usable compliance check
Most search results either define the public support test or sell a larger compliance platform. This page solves the immediate job first: use the tool, see the answer, and understand what it means before you move into a deeper Form 990 workflow.
The functional tool stays on top so users can solve the immediate problem before reading a guide.
The result cards explain what the output means instead of leaving users with a raw percentage.
Ledger Summit can build richer compliance tooling later, but this page delivers value now.
FAQ
IRS Public Support Test questions, answered directly
Written in short form so searchers can get a clear answer without digging through generic product copy.
The public support test is a calculation the IRS uses to determine whether a 501(c)(3) organization qualifies as a public charity under Section 509(a)(1) or 509(a)(2). The organization must receive at least 33.33% of its total support from public sources over a rolling 5-year period.
Section 509(a)(1) organizations rely on gifts, grants, and contributions for public support. Section 509(a)(2) organizations rely on gross receipts from activities related to their exempt purpose, subject to the greater-of-1% or $5,000 limitation per contributor.
An organization that fails the 33.33% mechanical test may still qualify under the 10% facts-and-circumstances test. If it fails both, it is reclassified as a private foundation, which carries stricter rules on self-dealing, payout requirements, and excise taxes.
No. The page runs the calculator in your browser and does not require a file upload for the base workflow.
Yes. If you need a richer model, recurring workflow automation, or an internal production version, Ledger Summit can build it around your process.
Next Step
Need this connected to a broader workflow?
Use the free browser tool first. If you need a richer model, reporting automation, or an internal production version, Ledger Summit can build the next layer around your process.
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