Tax Software vs. a CPA: An Honest Comparison

By Tom, CPA · Updated October 27, 2026

Part of: Tax Planning

TL;DR: Software is great at applying rules to the facts you enter and is enough for most simple returns. A CPA or enrolled agent earns their fee by spotting missing facts, elections and multi-year issues, and by representing you before the IRS. Many people do best with a hybrid.

Educational only, not tax, legal, or investment advice. Examples are illustrations, not predictions. Rules and limits change; verify current figures and talk to a qualified professional about your situation.

The tax code runs to millions of words, and tax software has read all of them. It has not read your situation. That is the whole software versus CPA debate in one sentence: software is excellent at applying rules to the facts you give it, and useless at noticing the facts you did not know mattered.

This comparison covers what software does well, what a CPA or enrolled agent adds, the credentials that matter, free options, cost thinking, red flags, and a decision guide by situation. It is written by a CPA, so take the bias warning seriously: plenty of people should use software, and this page will tell you who.

CPA Warning Label: You are responsible for your return no matter who prepares it. Avoid preparers who charge by refund size or will not sign, and verify credentials first.

Quick comparison

What software does well

• Math and forms. Software does not make arithmetic errors and keeps up with form changes, like the new deductions for tips, overtime, car loan interest and seniors that apply to 2025 through 2028.
• Imports. W-2s, 1099s and brokerage data import automatically from many providers.
• Interview logic. Good software asks about common situations and flags missing credits.
• Cost. For simple returns, nothing beats free. IRS Free File partners offer free guided software for taxpayers below an AGI limit set each year, and Free File Fillable Forms is available to everyone. VITA and TCE volunteer programs prepare returns free for qualifying taxpayers.
• Year-over-year carryforward. Using the same software each year preserves carryovers and basis data, if you stay put.

If your return is W-2 income, a few 1099-INT and 1099-DIV forms, maybe a 401(k) and an HSA, and the standard deduction, software is usually the right call.

Where software struggles

Software answers the question you ask. It does not ask whether you are asking the right question.

• Cost basis errors. RSU and ESPP sales with zero basis on Form 1099-B are double-taxed when entered as is. See RSU tax planning.
• Elections and choices. Electing qualified dividends into investment income, real estate professional status, de minimis safe harbor, section 179 versus bonus depreciation, and portability are judgment calls.
• Multi-year effects. A Roth conversion, a home sale or a large gift affects future years; software sees one year.
• Carryovers lost in transitions. Switching software often drops capital loss, passive loss or investment interest carryovers. See the capital loss limit.
• Garbage in. If you classify a worker, an expense or an account wrong, software will compute the wrong answer perfectly.

Credentials that matter

Anyone paid to prepare returns needs a preparer tax identification number (PTIN). Beyond that, credentials vary:

• CPA: licensed by a state board, passed the CPA exam, subject to continuing education and ethics rules. Unlimited representation rights before the IRS.
• Enrolled agent (EA): licensed by the IRS after passing a three-part tax exam or through IRS experience. Unlimited representation rights. Many EAs specialize in individual and small business tax.
• Tax attorney: best for legal disputes, criminal exposure, complex estate and business transactions.
• Unenrolled preparers have limited representation rights, generally only for returns they prepared and only before certain IRS employees, and only if they participated in the IRS Annual Filing Season Program.

Verify credentials in the IRS Directory of Federal Tax Return Preparers and with your state board of accountancy. A credential is not a guarantee of fit; ask about experience with your specific situation.

Red flags in any preparer

• Fees based on a percentage of your refund.
• Promises of a bigger refund before seeing your documents.
• Refusal to sign the return or include their PTIN ("ghost preparers").
• Asking you to sign a blank return or route your refund to their account.
• Pitching aggressive schemes: inflated credits, fake business losses, abusive trusts, or employee retention credit claims you do not qualify for.

You are legally responsible for your return, even if a preparer made the error. Penalties, interest and the bill come to you. See IRS penalties and interest.

Decision guide by situation

A hybrid often works: pay for a planning session in a complex year, then file with software in calmer years.

Questions to ask before hiring anyone

1. What kinds of returns do you prepare most? A preparer who mostly handles small business returns may not be the best fit for an early retiree juggling Roth conversions and ACA credits, and vice versa.
2. Who actually prepares and reviews the return? At some firms, a junior staff member prepares and a credentialed professional reviews. That is fine, as long as you know.
3. How is the fee set? Flat fee, hourly, or by form count are all normal. Percentage of refund is not.
4. Is planning included? Preparation looks backward. Planning looks forward. Many engagements include only preparation unless you ask.
5. What happens if I get an IRS notice? Find out whether responding to notices about returns they prepared is included or billed separately.
6. How do you handle document security? Expect a secure portal, not email attachments of your Social Security number.
7. When do you need my documents? Good preparers are booked solid in March and April. Early birds get attention; late arrivals get extensions.

An extension is not a failure, by the way. It extends the time to file, not the time to pay, so estimate and pay any balance by the April deadline to avoid late-payment penalties and interest.

Illustration: when a professional pays for itself

Illustration: a married couple sold $80,000 of RSU shares in 2026. Their 1099-B reported zero basis; the vest-date value was $70,000. They also bought a rental property in 2026 and paid $12,000 of repairs and improvements.

• Basis fix: entering the 1099-B as is reports $80,000 of gain instead of $10,000. At a 15% long-term rate, that is $10,500 of extra tax.
• Rental: classifying the $12,000 correctly between deductible repairs and capitalized improvements, and starting depreciation, could change rental income meaningfully, plus set up years of correct depreciation.

Whether they use a professional or software, the money is in catching those two items. Diligent software users can catch both; most do not know to look. A one-time professional review that costs a few hundred dollars is cheap relative to a $10,500 error.

Assumptions: shares held more than a year from vest; 15% rate; no state tax.

How to get the most from either

• Keep a tax folder all year: W-2s, 1099s, Form 1098, charity receipts, basis records, prior-year returns.
• Read your return before filing. See how to read Form 1040 and the Form 1099 guide.
• Get an IP PIN to block fraudulent filings. See tax identity theft and the IP PIN.
• If you use software, run a quick sanity check: compare this year's return to last year's line by line, and investigate any number that changed by more than you expected. Big swings in taxable income, refunds or credits usually point to a missing form or a mistyped entry.
• Save a PDF of the full return, including worksheets, not just the summary.
• If you hire someone, ask in advance what is included: preparation only, planning, notice response.

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