Most taxpayers facing an audit want one number: what will this cost. The honest answer is that fees vary meaningfully by audit type, complexity, and the posture of the case at the point of engagement. A CP2000 for a missing 1099 is not the same matter as a field audit on a Schedule C business, and the fees reflect that. This chapter explains how IRS audit defense fees are structured, what drives the variation, and how to evaluate whether the fee is appropriate for your matter.

Our firm has represented taxpayers in hundreds of audits as IRS audit defense counsel. We quote fees only after reviewing the notice and the return because under-scoped fees serve no one. The descriptions below reflect actual fee ranges we see across our practice and comparable California tax firms. For context on the audit process itself, see What Happens During an IRS Audit.

IRS audit attorney fees typically run $1,500–$5,000 for a correspondence audit, $10,000–$30,000 for an office audit, and $15,000–$75,000 or more for a complex field audit. Whether you need an attorney depends on the audit type, the dollars at issue, and whether criminal exposure or eggshell audit indicators are present. For most correspondence audits involving a single documentation issue, a CPA may be sufficient. For field audits, audits with fraud indicators, or any audit where the IRS is asking questions beyond document matching, attorney representation is the right call.

Watch: what to look for when hiring a tax attorney

The Four Fee Structures for IRS Audit Representation

Audit defense fees come in four structures. The right structure depends on the audit type, the complexity, and whether the scope is knowable at engagement. Each has advantages; none is inherently better.

Lowest CostFlat Fee
ModerateHourly
HighRetainer + Hourly
ComplexPhased Fee

IRS audit defense fee structures with typical fee range, audit type fit, advantages, and when to use each.
Structure Typical Range Best Fit Advantage Disadvantage2
Flat Fee $1,500 – $15,000 Correspondence / Office Cost certainty Scope must be clear
Hourly $400 – $850 / hr Unscoped matters Pay for actual work Cost uncertainty
Retainer + Hourly $10K retainer + hourly Field audits Flexibility Possible overrun
Phased Fee Per phase Complex / multi-year Re-scope at milestones Multiple decision points

Quick Reference

Jump to the fee structure that fits your situation: flat fee, hourly, retainer, or phased fee. For what fees typically run by audit type, see the fee lookup table. To get a specific scope for your notice, a 15-minute consultation is free.

1. Flat Fee: Cost Certainty for Scoped Matters

A flat fee is a fixed, engagement-wide fee quoted in advance based on the known scope of the audit. Flat fees are most common on correspondence and office audits, where the scope is defined by the IDR and the issues on the notice. The taxpayer pays the fee at engagement or in installments, and the representation is included for the life of the matter.

If this is you: You have a correspondence audit (CP2000, Letter 566) or a straightforward office audit. The letter lists specific items and a specific deadline. A flat fee gives you cost certainty — you know what you will pay before the work starts. This is usually the right structure when the scope is knowable.

Flat fees at Brotman Law and comparable California firms typically run:

  • CP2000 or AUR mismatch correspondence audit: $1,500 – $3,500 depending on complexity
  • Letter 566 substantiation request: $2,500 – $5,000
  • Office audit (Letter 915 / 3572): $5,000 – $15,000
  • Simple Schedule C field audit, single year: $15,000 – $25,000 (when scoped as flat)

The short version is that a flat fee works when two conditions are met. First, the attorney can define the scope in advance — specific issues, specific year, specific response deliverable. Second, the scope is unlikely to expand mid-engagement. When either condition is uncertain, hourly or phased structures are usually a better fit for the taxpayer.

When to Choose a Flat Fee

  1. The audit is correspondence or office level. Scope is reasonably contained to the notice.
  2. The substantive issues are identified in writing. The IDR or notice is specific.
  3. You want budget certainty. Cost management is a priority.
  4. You have no reason to expect scope expansion. No cash deposits, no offshore accounts, no criminal concerns.
  5. You have reviewed the scope definition in writing. A flat-fee engagement letter should list what is included and what is not.

2. Hourly: Pay for the Work Actually Done

An hourly structure charges the taxpayer for each hour the attorney and team work on the matter, typically billed monthly. Hourly rates in California tax practice generally range from $400 to $850 per hour for attorney time, with paralegal and support time at lower rates. Hourly is the default for unscoped or evolving matters.

If this is you: Your audit scope is not clear, or it is likely to change. A field audit with unknown depth, an audit that has already expanded once, or a matter with potential for civil-to-criminal escalation. Hourly billing means you pay for actual work rather than a speculative scope. The tradeoff is cost uncertainty.

Hourly billing is common on field audits, audits with multi-entity exposure, and any matter where the attorney cannot responsibly scope a flat fee. A typical hourly structure includes an initial retainer (commonly $5,000 to $20,000) drawn down against time billed, with additional retainers replenished as the balance falls.

An important point for context: hourly rates vary by firm tier and attorney seniority. A solo practitioner with a decade of tax experience may bill $400–$500 per hour. A senior tax attorney at an established firm commonly bills $600–$850 per hour. The rate itself is less important than the efficiency of the time billed and the outcome produced.

When Hourly Makes Sense

  1. Scope is genuinely unknowable at engagement. Field audit with unknown breadth, case with criminal potential.
  2. The matter is likely to compress or expand in ways hard to predict. Examiner posture is unknown.
  3. You value paying for actual work over budget certainty.
  4. You have received detailed billing practices from the attorney. Minimum billing increments, what gets billed, how communications are billed.

3. Retainer Plus Hourly: The Standard Field Audit Structure

A retainer-plus-hourly engagement combines an upfront retainer with hourly billing against that retainer. This is the most common structure for field audits, Appeals-bound matters, and any case that will involve meaningful attorney time across multiple phases.3

If this is you: You have a field audit (Letter 2205-A or 2205-B), an audit heading to Appeals, or a multi-year case. The retainer secures engagement and covers the initial phase; hourly billing tracks the actual work thereafter. The retainer is refundable if work stops before it is drawn down.

Retainers for field audits typically run $10,000 to $25,000 at engagement, with the balance drawn against hourly time. When the retainer is exhausted, a replenishment is requested. Some firms require the retainer to be maintained at a minimum balance; others bill monthly against a starting retainer and replenish only when it reaches zero.

The short version is that this structure offers the attorney predictable cash flow and the taxpayer flexibility. The downside is that total cost is not knowable at engagement. A field audit can close in 8 hours of attorney time or 100, depending on examiner posture, complexity, and whether Appeals or Tax Court becomes necessary.

Retainer Structure Best Practices

  1. Ask for a written engagement letter that defines refund terms. Unearned retainer is the client’s money.
  2. Request monthly billing statements with detail. Line-item time entries by attorney, task, and duration.
  3. Confirm what triggers replenishment. Minimum balance, percentage draw, or exhaustion.
  4. Ask about caps. Some firms offer a not-to-exceed cap on total hourly fees for a defined phase.
  5. Verify who is billing. Partner time, associate time, paralegal time — each at a different rate.

4. Phased Fee: Re-Scope at Each Milestone

A phased fee structure quotes a separate fee for each phase of the audit. Common phases are initial response, examination, closing conference, Appeals, and Tax Court. Each phase has its own fixed fee, and the taxpayer decides whether to engage for the next phase when the current one closes.4

If this is you: You have a complex or multi-year matter and want the flexibility to re-evaluate representation at each stage. Phased fees give you decision points — after the examiner’s initial response, after Form 4549, after Appeals — and the option to walk, continue, or change counsel at each.

A typical phased structure for a field audit might look like:

  • Phase 1 — Pre-engagement and document production: $10,000
  • Phase 2 — Examiner meetings and IDR responses: $15,000
  • Phase 3 — Closing conference and 30-Day Letter: $7,500
  • Phase 4 — IRS Appeals: $10,000 – $25,000
  • Phase 5 — Tax Court petition and trial: Separate engagement, typically $50,000+

In our experience, phased fees work best for taxpayers who want control over total spend and who are prepared to make a fresh engagement decision at each phase. The tradeoff is transaction cost — each phase requires a new decision, a new engagement letter, and potentially a new retainer.

Received a field audit notice with a 10-business-day deadline? Field audits require representation before the initial interview. The Revenue Agent’s first meeting shapes the trajectory of the examination. Book a call to scope fees and representation before that meeting.

Fee Lookup: What Representation Costs by Audit Type

The table below summarizes typical fee ranges by audit type and by the document that triggered engagement. These are ranges, not quotes — actual fees depend on complexity, examiner posture, and scope.

IRS audit defense fee ranges by audit type, triggering document, typical structure, and cost.
Notice / Audit Type Typical Structure Fee Range
CP2000 Flat fee $1,500 – $3,500
Letter 566 Flat fee $2,500 – $5,000
CP75 / CP75A (EITC) Flat fee $1,500 – $4,000
Letter 915 / 3572 (Office) Flat fee $5,000 – $15,000
Letter 2205-A (Field, individual) Retainer + hourly $15,000 – $35,000
Letter 2205-B (Field, business) Retainer + hourly $25,000 – $75,000+
Multi-entity field audit Phased fee $50,000 – $200,000+
NRP research audit Retainer + hourly $20,000 – $50,000
IRS Appeals Hourly or phased $10,000 – $25,000
Tax Court petition New engagement $25,000 – $150,000+
Criminal Investigation referral Separate CI defense $100,000+

How Long Does Representation Actually Last?

Fee scoping depends on duration. The statute of limitations under IRC §6501 sets outer bounds; actual case duration is usually shorter.

  • Correspondence audits: 3 to 6 months. Most flat-fee representations span this window.
  • Office audits: 6 to 12 months. Single meeting, follow-up IDRs, closing.
  • Field audits: 12 to 24 months. Multiple visits, IDRs, interviews, and Appeals possibility.
  • Appeals: 6 to 12 additional months. Administrative review and settlement.
  • Tax Court: 1 to 2 additional years. Petition, pretrial, and trial calendar.

The practical implication is this: fees span years in contested matters. A taxpayer who receives a field audit notice today may still be engaged with counsel in 2029 if the case goes through Appeals and Tax Court. Engagement letters should address what happens in year three.

Fee Ranges Observed in California Tax Practice

The table below summarizes fee data drawn from published rate surveys, industry salary data, and Brotman Law’s practice experience with comparable matters. These figures are representative of California tax firms; rates elsewhere may differ.

Typical California IRS audit defense fee ranges by matter type. Source: Brotman Law practice metrics; California Bar published rate data; TaxProTalk industry survey data.
Matter Type Fee Range
Correspondence audit (CP2000) $1,500 – $3,500
Correspondence audit (substantiation) $2,500 – $5,000
Office audit $5,000 – $15,000
Field audit (individual) $15,000 – $35,000
Field audit (small business) $25,000 – $75,000
Multi-entity field audit $50,000 – $200,000+
Hourly rate (senior tax attorney) $600 – $850 / hr
Hourly rate (associate) $300 – $550 / hr
Hourly rate (paralegal) $150 – $275 / hr

Rates in 2026 have trended upward with general legal-industry inflation. California field-audit fees at established firms commonly start at $20,000; the $10,000 figure once common a decade ago is rare today for comparable scope.

The Fee Escalation Pathway

Fees, like audits, escalate. Understanding how fees change at each stage helps the taxpayer plan.

Correspondence to Office or Field

A correspondence audit that escalates to office adds roughly $4,000 to $10,000 to the total cost. Escalation to field adds $10,000 to $30,000 or more. The majority of escalation cost is avoidable through disciplined Stage 2 response — volunteered information is both an audit-widener and a fee-multiplier.

Office to Field

When an office audit escalates to field, the fee structure typically changes from flat to retainer-plus-hourly. The additional cost reflects the broader scope, multiple site visits, and longer duration. Once escalated, the case stays at field.

Field to Appeals or Tax Court

Appeals typically runs $10,000 to $25,000 as a separate engagement. Tax Court adds another $25,000 to $150,000 depending on complexity. A fully contested multi-year field audit with Appeals and Tax Court can produce combined fees of $75,000 to $300,000+. These figures sound large; they are almost always a fraction of the proposed deficiency when the audit is over $100,000.

The practical implication is this: engaging counsel earlier in the audit — before escalation — produces lower total cost and better outcomes than engaging after escalation has occurred.

The First 48 Hours: How to Scope a Fee

The sequence below reflects how our firm scopes a fee when a new taxpayer contacts us. Most established tax firms follow a similar process.

  1. Intake call (free, 15 minutes). Attorney reviews the notice, identifies audit type and deadline, and discusses the taxpayer’s situation.
  2. Notice and return review. Attorney reads the full notice, the IDR if issued, and the tax return under examination.
  3. Fee scoping call. Attorney proposes structure (flat, hourly, retainer, phased) and quotes a specific fee range.
  4. Engagement letter issued. Written scope, fee, refund terms, and representation boundaries.
  5. Taxpayer review period. 24 to 72 hours to review and ask questions.
  6. Engagement letter signed and retainer paid.
  7. Form 2848 Power of Attorney filed. IRS contact redirects to the firm.

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Brotman Law has been recognized by Inc. Magazine as one of California’s fastest-growing law firms. We have represented taxpayers across the full audit fee spectrum — from $2,000 CP2000 flat fees to seven-figure phased engagements — and we quote fees only after reviewing the notice. Free 15-minute intake calls are available to scope the matter and give an honest fee estimate. Our office is based in San Diego, and we represent clients throughout California and nationwide.

The ROI Question

For audits with proposed deficiencies above $100,000, the representation fee is almost always less than the combined tax, penalty, and interest exposure. The 75% civil fraud penalty under IRC §6663 alone can exceed the entire cost of a fully contested Tax Court proceeding. The decision is rarely about whether to engage counsel. It is about whether to engage counsel before or after the IRS finalizes the assessment.

Under IRS Audit?

Every audit has a scope — and keeping it contained is often as important as resolving the original issue. Responding without counsel can allow auditors to expand the examination, look at additional years, or introduce issues that weren’t in the original notice. Whether you’ve just received a notice or you’re already in the middle of an audit, we can review where things stand.

Discuss My IRS Audit →    Or call: (619) 378-3138

When to Engage an IRS Audit Attorney

Not every audit requires counsel. A CP2000 for a missing 1099 that can be documented in 20 minutes generally does not warrant professional representation. The situations below are the ones where the representation fee is almost always less than the cost of self-representation.

  • Field audit notice (Letter 2205-A or 2205-B). The 10-business-day deadline and the initial interview require preparation that a self-represented taxpayer usually cannot complete in time.
  • Proposed deficiency above $10,000. The ROI calculation favors counsel almost every time.
  • Business returns — Schedule C, S-corp, partnership, multi-entity. Business audits expand without discipline.
  • Any penalty language on the report. IRC §6662 (accuracy, 20%–40%) or §6663 (fraud, 75%) require preserved defenses.
  • Bank deposit or cash questions. These are pre-criminal indicators. Representation should be in place before the next meeting.
  • Foreign accounts or cryptocurrency. FBAR and digital asset reporting carry exposure beyond the tax.
  • 30-Day Letter or Notice of Deficiency received. Deadlines are strict.

Any of the above apply to your situation?

A 15-minute consultation is free. We will review the notice, scope a fee range, and give you a candid assessment of whether representation is warranted. If it is not, we will tell you.

Get a Candid Assessment — Free →

For a full overview of how Brotman Law approaches audit representation — response strategy, privilege protection, and what the process looks like from notice to close — see our IRS audit defense service page.