What Are the Basic Rules of a 501(c)(3) Nonprofit?

A 501(c)(3) nonprofit has to meet a defined set of rules under Section 501(c)(3) of the Internal Revenue Code to earn tax-exempt status and a further set to keep it. In short: the organization must be built and run for a recognized exempt purpose, it cannot campaign for or against political candidates, its lobbying must stay limited, no insider can profit from it, it has to file an annual return with the IRS, it still owes payroll taxes on employees, it may owe tax on business income unrelated to its mission, and it must make key filings public and give donors proper acknowledgments. Most of the compliance failures the IRS sees come from a small number of these rules, and they are avoidable.

What Qualifies as a 501(c)(3)

Two tests decide whether an organization qualifies. The organizational test looks at the founding documents. Your articles of incorporation or trust agreement must limit the organization’s activities to one or more recognized exempt purposes, must not authorize non-exempt activities except in a trivial way, and must dedicate remaining assets to another exempt organization or a government entity if the nonprofit dissolves.¹

The operational test looks at what the organization actually does. Its activities must primarily further its exempt mission; if more than an insubstantial part of the work serves non-exempt goals, the IRS will deny or revoke the exemption.¹ Failing either test disqualifies the organization no matter how worthy the stated purpose sounds.

The recognized exempt purposes under the statute are charitable, religious, educational, scientific, literary, testing for public safety, fostering amateur sports competition (as long as the organization does not provide athletic facilities or equipment), and prevention of cruelty to children or animals.² The IRS reads “charitable” broadly, covering relief of the poor, advancement of education or religion, and community betterment.

Political Campaigning Is Prohibited

This rule is categorical. A 501(c)(3) cannot participate or intervene in any political campaign for or against a candidate for public office.² No contributions to candidate committees, no endorsements, no public statements favoring one candidate over another. Violations can cost the organization its exempt status and trigger excise taxes on the amount spent.³

The excise taxes under Section 4955 come in layers. The organization pays 10% of the political expenditure and any manager who knowingly approved it pays 2.5%. If the expenditure is not corrected within the required period, an additional 100% tax on the organization and 50% on the refusing manager apply.⁴ These penalties sit alongside possible revocation, not instead of it.

Lobbying Is Allowed Within Limits

Lobbying is treated differently. A 501(c)(3) can try to influence legislation, but lobbying cannot become a substantial part of its overall activities.² The word “substantial” is intentionally vague under this default test, which is why many nonprofits that lobby make the Section 501(h) election instead. That election replaces the subjective test with concrete dollar limits on a sliding scale tied to exempt-purpose expenditures, capped at $1,000,000 in lobbying spending regardless of the organization’s size. As a starting point, an organization with up to $500,000 in exempt-purpose expenditures may spend up to 20% of that on lobbying.⁵

Churches and private foundations cannot make the 501(h) election.⁶ Everyone else can use it as a measurable safe harbor that avoids arguments about what counts as substantial.

No Private Inurement or Excess Benefits

No part of a 501(c)(3)’s net earnings may benefit any private shareholder or individual.² This is the private inurement rule, and it targets insiders: officers, directors, trustees, key employees, and their family members. When an insider receives compensation or benefits above what the role is actually worth, the IRS treats the excess as an “excess benefit transaction.”

The insider who received the excess benefit pays an excise tax of 25% of that amount. If the problem is not corrected within the required window, an additional 200% tax applies.⁷ These intermediate sanctions give the IRS a tool short of full revocation, but revocation stays on the table for serious or repeated violations.¹

The related concept of “private benefit” reaches beyond insiders to anyone. Even if no board member profits, the organization can lose its exemption if a program primarily enriches a specific group of people or businesses rather than serving the public. Some incidental private benefit is expected in normal operations, but it cannot be the point of the program.

The practical protection is process. Reasonable compensation is judged against comparable positions at comparable organizations. The safest approach is to have the board or an independent committee review compensation using independent salary data and document the decision in meeting minutes. The IRS also strongly encourages every 501(c)(3) to adopt a written conflict of interest policy requiring directors and staff to disclose financial interests in entities that do business with the organization.⁸ Form 990 specifically asks whether the organization has a conflict of interest policy, a whistleblower policy, and a document retention policy.⁹ None of these are strictly required, but “no” answers tend to invite scrutiny.

Filing an Annual Return

Nearly every 501(c)(3) has to file an annual information return. The form depends on the organization’s size:

Gross receipts of $50,000 or less: Form 990-N, the electronic “e-Postcard.”¹⁰
Gross receipts under $200,000 and total assets under $500,000: Form 990-EZ or the full Form 990.
Gross receipts of $200,000 or more, or total assets of $500,000 or more: the full Form 990.¹¹

The return is due by the 15th day of the fifth month after the end of the accounting period. For a calendar-year organization, that is May 15.¹² Extensions are available.

One deadline gets no exceptions. If an organization fails to file any required return for three consecutive years, its tax-exempt status is automatically revoked, with no warning letter and no hearing. The revocation takes effect on the filing due date of the third missed year.¹⁰ Short of that three-year trigger, late filing carries daily penalties: organizations with gross receipts under $1,208,500 pay $20 per day up to the lesser of $12,000 or 5% of gross receipts, and larger organizations pay $120 per day up to $60,000.¹³

Payroll Taxes Still Apply

Tax-exempt does not mean exempt from all federal taxes. Any 501(c)(3) with employees must withhold and pay Social Security and Medicare taxes (FICA), and must withhold federal income tax from wages, just like any other employer. The organization also pays the employer’s matching share of FICA.¹⁴

There is one break: 501(c)(3) organizations are exempt from federal unemployment tax (FUTA).¹⁴ Payroll taxes are reported on Form 941 each quarter, or Form 944 annually for very small employers. Getting payroll wrong is one of the most common early failures, often because board members assume the “exempt” label covers wages.

Income From Unrelated Business Is Taxable

When a 501(c)(3) regularly carries on a trade or business that is not substantially related to its exempt purpose, the income is subject to unrelated business income tax (UBIT). If gross income from unrelated business activities hits $1,000 or more, the organization must file Form 990-T and pay tax on the net income at regular corporate rates.¹⁵ The statute also provides a $1,000 specific deduction against unrelated business taxable income.¹⁶

Several categories are excluded from UBIT even if unrelated to the mission:

Passive investment income: dividends, interest, annuities, rents from real property, and royalties.
Activities in which substantially all the work is performed by unpaid volunteers.
Sales of merchandise that was donated to the organization.
Activities run primarily for the convenience of members, students, patients, or employees.
Qualified sponsorship payments that do not amount to advertising.

The volunteer and donated-goods exclusions matter most in practice. A charity that runs a weekend car wash staffed entirely by volunteers does not owe UBIT on the proceeds, even though car washing has nothing to do with its mission. Hire staff to run the same car wash every Saturday as an ongoing revenue stream, and the income is likely taxable.

Public Disclosure of Filings

Transparency is part of the deal. A 501(c)(3) must make its original exemption application (Form 1023 or 1023-EZ) and its three most recent annual returns available for public inspection.¹⁷ Anyone can request them. The organization must make them available at its office during business hours or provide copies by mail. The IRS also publishes these filings, and third-party sites like GuideStar make them easily searchable. Willful failure to comply with the public inspection rules can result in a $5,000 penalty per return or application.

Donor Receipts and Acknowledgments

A donor who contributes $250 or more in a single transaction needs a written acknowledgment from the organization to claim a tax deduction. The acknowledgment must state the cash amount or describe any donated property, and it must note whether the organization provided anything in return.¹⁸

Different rules apply when the donor gets something back. When a payment exceeds $75 and the donor receives goods or services in return, such as a dinner or tickets, the organization must provide a written disclosure stating that only the portion of the payment exceeding the fair market value of what the donor received is deductible, and giving a good-faith estimate of that value. If a donor pays $150 for a fundraising dinner where the meal is worth $50, the deductible portion is $100. The disclosure must accompany either the solicitation or the receipt of the contribution.¹⁸

Non-cash gifts trigger extra donor paperwork that scales with claimed value. Donors claiming a deduction of more than $500 for non-cash gifts file Form 8283 with their return, and once the claimed value exceeds $5,000, a qualified appraisal is generally required.¹⁹ These are donor obligations, but donors usually look to the nonprofit for guidance.

Public Charity vs. Private Foundation

Every 501(c)(3) is classified as either a public charity or a private foundation, and the rules diverge. Public charities generally receive broad financial support from the public, government grants, or other public charities, and qualify through the “public support test” under Sections 509(a)(1) and 170(b)(1)(A)(vi) or under Section 509(a)(2).²⁰ Any 501(c)(3) that does not affirmatively qualify as a public charity is treated as a private foundation by default.

Private foundations, typically funded by a single family or a small group of donors, face rules that do not apply to public charities. These include an outright ban on financial transactions with insiders (self-dealing) and a requirement to distribute a minimum amount annually for charitable purposes. Falling short triggers a 30% excise tax on the undistributed income, rising to 100% if the shortfall is not corrected after IRS notification.²¹ The classification is made during the application process, and it changes which rules bind the organization for the rest of its life.

Getting Reinstated After Losing Status

If the three-year filing rule catches up with the organization, reinstatement is possible on one of three tracks.²²

Streamlined retroactive reinstatement is available to organizations small enough to file Form 990-EZ or 990-N during the missed years and that have not been auto-revoked before. You must apply within 15 months of the revocation notice or the date the organization appeared on the IRS Revocation List, whichever is later.
Retroactive reinstatement within 15 months is for organizations required to file the full Form 990, or that have been auto-revoked before. Same deadline, but you must also submit a statement showing reasonable cause for missing at least one of the three filing years, plus all delinquent returns.
Retroactive reinstatement after 15 months is still possible, but you must show reasonable cause for missing all three years, not just one.

Every track requires paying the application user fee again. During the gap between revocation and reinstatement, the organization is not tax-exempt, income earned may be taxable, and donations may not be deductible. The lesson is simple: even a tiny nonprofit that only files the e-Postcard should file it every year.

1
eCFR. 26 CFR 1.501(c)(3)-1 – Organizations Organized and Operated for Religious, Charitable, Scientific, Testing for Public Safety, Literary, or Educational Purposes, or for the Prevention of Cruelty to Children or Animals
2
Office of the Law Revision Counsel. 26 USC 501 – Exemption From Tax on Corporations, Certain Trusts, Etc.
3
Internal Revenue Service. Frequently Asked Questions About the Ban on Political Campaign Intervention by 501(c)(3) Organizations – Consequences of Prohibited Activity
4
Office of the Law Revision Counsel. 26 USC 4955 – Taxes on Political Expenditures of Section 501(c)(3) Organizations
5
Internal Revenue Service. Measuring Lobbying Activity: Expenditure Test
6
Office of the Law Revision Counsel. 26 USC 4911 – Tax on Excess Expenditures to Influence Legislation
7
Office of the Law Revision Counsel. 26 USC 4958 – Taxes on Excess Benefit Transactions
8
Internal Revenue Service. Governance and Related Topics – 501(c)(3) Organizations – Good Governance Practices
9
Internal Revenue Service. Form 990, Part VI – Governance, Management, and Disclosure Frequently Asked Questions
10
Internal Revenue Service. Annual Electronic Filing Requirement for Small Exempt Organizations – Form 990-N (e-Postcard)
11
Internal Revenue Service. Form 990 Series Which Forms Do Exempt Organizations File Filing Phase In
12
Internal Revenue Service. Annual Exempt Organization Return: Due Date
13
Internal Revenue Service. Late Filing of Annual Returns
14
Internal Revenue Service. Exempt Organizations: What Are Employment Taxes
15
Internal Revenue Service. 2025 Instructions for Form 990-T – Exempt Organization Business Income Tax Return
16
Office of the Law Revision Counsel. 26 USC 512 – Unrelated Business Taxable Income
17
Internal Revenue Service. Public Disclosure and Availability of Exempt Organizations Returns and Applications: Documents Subject to Public Disclosure
18
Internal Revenue Service. Substantiating Charitable Contributions
19
Internal Revenue Service. Publication 561 Determining the Value of Donated Property
20
Internal Revenue Service. Determine Your Foundation Classification
21
Internal Revenue Service. Taxes on Failure to Distribute Income – Private Foundations
22
Internal Revenue Service. Automatic Revocation – How to Have Your Tax-Exempt Status Reinstated