Nonprofit audit requirements aren't one-size-fits-all—they hinge on your organization's size, funding sources, and state regulations. Getting the frequency wrong costs you credibility with donors, puts you at compliance risk, and can delay grant funding. Here's what you need to know to audit on schedule and budget.
Legal Requirements: What the Numbers Say
Most nonprofits must undergo an audit if they receive federal grants exceeding $750,000 in a fiscal year under the Single Audit Act. Below that threshold, many states have their own requirements—typically triggered at $500,000 to $1 million in revenue, though some require audits for any organization receiving state funds.
If your nonprofit falls below these thresholds, you still might need an audit if your bylaws require it, your board decides it's prudent, or your donors specifically request one. Check your state's Attorney General's office and your funding agreements to confirm what applies to you.
Annual Audits vs. Biennial Audits
Annual audits are standard practice for organizations above the federal Single Audit threshold and recommended for those with complex finances, multiple funding sources, or significant donor concerns. Expect costs between $3,000–$10,000+ annually depending on your organization's size and operational complexity.
Biennial audits (every two years) are permissible in some states for smaller nonprofits and can reduce costs. However, they still require filing annual Form 990s with the IRS. A biennial schedule makes sense only if your revenue is stable, you have solid internal controls, and state law permits it.
When to Add More Frequent Reviews
Even if annual audits aren't legally mandated, consider them if:
- You manage restricted grants or multi-year funding agreements
- Your revenue or assets exceed $5 million
- You have significant turnover in finance staff
- Donors or board members have flagged concerns
- Your organization has experienced fraud or control weaknesses
- You're scaling programs rapidly
In these cases, a full audit every year—or at minimum a financial review engagement—protects your reputation and catches problems early.
The Form 990 Timeline and Coordination
Your Form 990 filing is due 4.5 months after your fiscal year ends (or 8.5 months with an extension). An audit must be completed before filing, so plan backwards: if your year ends December 31, your audit firm needs to wrap up by mid-April at the latest.
Many nonprofits coordinate their annual audit with their Form 990 preparation. A single provider handling both saves time and ensures consistency. Audit firms typically charge $1,500–$3,500 extra for Form 990 preparation on top of audit fees, depending on complexity.
Cost Factors and Timeline
Audit costs vary widely based on:
- Organization size: $500K revenue might cost $2,500–$4,000; $5M+ could run $8,000–$20,000+
- Complexity: Multiple locations, international programs, or specialized accounting methods add 20–40% to fees
- Internal controls: Strong documentation and clean records reduce fieldwork time
- Timeliness of records: Disorganized records or late-closing processes delay completion and inflate costs
Most audits take 40–80 hours of fieldwork plus report writing. From kickoff to final report typically takes 8–12 weeks.
Choosing Your Audit Service Provider
When evaluating audit firms, ask specifically about:
- Experience with your nonprofit's size and sector (education, healthcare, arts, etc.)
- References from similar organizations they've audited
- Whether they integrate Form 990 filing and can advise on compliance beyond the audit
- Their timeline and availability during your busy season
- Fee structure (fixed price vs. hourly) and what's included
You can compare auditors and Form 990 service providers on Mercoly, which helps you find and evaluate trusted firms in one place without endless research.
A Simple Audit Schedule Strategy
Create a three-year planning window: map your actual audit requirement date, add buffer time (3 months minimum), and book your firm by that deadline. Build audit costs into your annual budget and set aside a contingency of 10–15% for unexpected complexity.
Document any significant changes to programs, staffing, or operations—your audit firm needs these details to scope work accurately.
Frequently Asked Questions
Q: Do I need an audit if I'm a small nonprofit under $500K in revenue? Not legally, but a financial review engagement (less expensive than a full audit, $1,000–$2,000) builds donor confidence and catches control issues early.
Q: Can the same person handle both my audit and Form 990 filing? Yes—many audit firms bundle both services, which streamlines the process and costs less than hiring separate providers.
Q: What happens if we don't complete the audit by the filing deadline? You can file Form 990 with an extension and note that an audit is pending, but delays damage donor trust and may trigger funder questions.
Compare audit providers today to lock in your 2024 compliance and budget.