Short answer
Not automatically. Under the ABA Model Rules framework, using AI does not by itself set a new percentage or require every lawyer to reduce a contingency fee. But a contingency fee must still be reasonable. The ABA’s Formal Opinion 512 says the Rule 1.5 fee reasonableness factors also apply when a lawyer charges a flat or contingent fee after using generative AI. It gives an example where charging the same flat fee after AI makes the work much faster may be unreasonable, and says a fee for which little or no work was performed is unreasonable.
That is a reason to assess the actual agreement and circumstances, not a mathematical rule that every saved minute must be deducted from a contingency percentage. The opinion does not prescribe a universal AI discount, a percentage reduction, or a rule that the fee must track hours in every matter. The client’s state rules, the written agreement, the work actually performed, the result, any financing or case-related risks the lawyer actually assumed, and applicable statutes or court rules matter. These risk examples describe possible facts to investigate; they do not establish that a lawyer in a particular case advanced costs, bore a given risk, or turned away other work.
First, identify what “contingency fee” means in your agreement
A contingency agreement typically makes the lawyer’s fee depend on an outcome, often by specifying a percentage of a recovery. It is different from an hourly arrangement, where the bill is based on recorded time, and from a flat fee, where the agreed amount covers defined work. Some engagements combine a percentage with client-paid costs or other provisions. Read the signed agreement rather than assuming that “no win, no fee” means there can never be expenses.
Under ABA Model Rule 1.5(c), a contingency-fee agreement must be in a writing signed by the client. In the Model Rule text, it states how the fee is calculated, including percentages for settlement, trial, or appeal; explains how litigation and other expenses are deducted and whether those expenses come out before or after the fee calculation; and identifies expenses the client owes even if there is no recovery. At the end, the lawyer provides a written statement of the result and, if there is a recovery, the client’s remittance and how it was calculated.
State rules and statutes can add requirements, cap percentages in some cases, or prohibit contingency fees for certain matters. The ABA Model Rule itself identifies criminal defense and certain domestic-relations matters as prohibited categories, while also recognizing that other law may limit fees. Check the jurisdiction governing the representation and the type of matter.
What the ABA guidance says about AI and fees
ABA Formal Opinion 512, issued in 2024, discusses generative AI under the ABA Model Rules as amended by the ABA House of Delegates through August 2023. It is useful guidance, but it does not reflect later ABA amendments to Model Rule comments adopted in August 2026, including amendments to Rules 1.4 and 1.5. The ABA’s Rule 1.4 communication text is another reference point for client communication. Nor does an ABA amendment automatically change a state's rules. For a particular representation, check the current rules adopted in the jurisdiction that governs it. On fees, Opinion 512 draws distinctions among billing methods:
| Fee or charge type | What the ABA guidance says | Practical question to ask |
|---|---|---|
| Hourly billing | If the lawyer bills by the hour, the lawyer bills actual time spent on the client’s matter. AI-generated work does not justify recording hours that were not spent. Time to provide information to the tool and to review its output may be billable if actually spent and otherwise reasonable. | Does the invoice show actual time, and were entries for AI-assisted work recorded accurately? |
| Flat or contingency fee | The Rule 1.5(a) reasonableness factors continue to apply. Opinion 512 says that if AI makes the work much faster, keeping the same flat fee may be unreasonable in some circumstances; it also says a fee for little or no work is unreasonable. The opinion applies these reasonableness principles to contingent fees too. | Does the agreed amount remain reasonable in light of the agreement, work, difficulty, risk, result, and applicable law? |
| AI as an expense | A charge must be reasonable and its basis communicated, preferably in writing, before or within a reasonable time after the engagement begins; before charging for AI, Opinion 512 says the lawyer must explain the basis, preferably in writing. A tool that functions like practice equipment is generally overhead absent advance disclosure otherwise. A matter-specific third-party service billed per use may ordinarily be charged as an expense at the actual out-of-pocket cost. For a proprietary in-house tool, the firm may agree in advance on a specific charge; absent such an agreement, Opinion 512 describes a limit of direct cost, if any, plus a reasonable allocation of directly associated expenses, with appropriate disclosure and no duplicate charges. | Is this a real, matter-specific charge, explained in advance and permitted by the agreement and local rules, or ordinary firm overhead? |
The opinion also says a lawyer generally may not bill a client to learn how to use an AI tool the lawyer expects to use across client matters, because maintaining competence is the lawyer’s responsibility. If the client specifically asks the lawyer to use a particular tool and the lawyer must learn it for that matter, the opinion says billing may be appropriate in some circumstances, provided the lawyer and client agree on the new billing terms first, preferably in writing.
These are ABA ethics interpretations tied to the ABA Model Rules. They are not a nationwide statute or a ruling that automatically resolves a dispute. A state disciplinary authority, court, statute, fee agreement, or other governing law may produce a different or more specific result.
Why time savings do not translate mechanically into a contingency discount
An hourly invoice asks how much time was actually spent, subject to reasonableness and the engagement terms. A contingency agreement generally sets a fee by a percentage or other outcome-based method, not by multiplying hours by an hourly rate. A case can also demand work that is hard to predict at the outset. Depending on the actual agreement and facts, a lawyer might assume the risk of receiving no fee, finance or carry case costs, forgo other work, or spend substantial time on investigation, negotiation, litigation, or appeal. Do not presume any of those factors without evidence in the particular engagement.
AI may reduce one task, such as sorting a large set of documents or producing a first draft. It may also create review and verification work, or prove unsuitable for sensitive or consequential tasks. A tool’s apparent speed does not establish that the matter as a whole required little professional work or that a fee is unreasonable. Nor does a strong result alone establish that any particular fee is reasonable. That is an inference from Rule 1.5's multi-factor reasonableness test: the amount involved and results obtained are among the factors, but neither replaces consideration of the other relevant circumstances. The rule does not provide a single hours-only formula.
For a broader discussion of human review and client protections in AI-assisted U.S. legal work, see our patent-practice workflow guide. Its subject is different, and it does not change the fee analysis here.
The useful question is therefore not “How many minutes did AI save, and what percentage must be removed?” It is “Does this fee remain reasonable under the governing rules and this agreement, given the services actually delivered and the circumstances of the representation?” The client can ask the lawyer to explain how the fee works and how AI-related charges, if any, fit within it. For evaluating a tool’s output quality separately from the fee question, see our legal AI accuracy guide.
Questions to ask before signing or when reviewing a fee
- What exactly is the fee? Is it a percentage of the gross recovery or of what remains after specified costs? Does the percentage change at settlement, trial, or appeal?
- Which costs might I owe? Are filing fees, expert fees, records, deposition costs, or other disbursements deducted from recovery? Could I owe any costs if there is no recovery?
- Is there a separate AI charge? Ask what the charge covers, whether it is a recurring subscription or a matter-specific service, how it is calculated, and where the agreement authorizes it.
- How will AI affect the fee arrangement? Ask whether the lawyer expects to use AI for material work and whether that changes the fee, costs, workflow, or client instructions. The answer depends on the agreement and local rules; the ABA framework does not mandate a preset discount.
- How is confidential information handled? Before client information is entered into a tool, ask what data the tool retains, who can access it, whether it is used to train or improve the service, and what safeguards apply. Our guide to legal AI data governance covers the separate operational questions a firm should evaluate. A legal AI data-processing agreement checklist offers a document-focused way to review service terms. Formal Opinion 512 treats confidentiality as a separate obligation; a generic fee conversation does not answer it.
- What if the work or circumstances change? Any change in the fee basis or expenses should be communicated. Under the Model Rule framework, a modification should be reasonable in the circumstances and communicated to and accepted by the client.
- Can I get the calculation in writing? Keep the signed contingency agreement, amendments, cost explanations, and the closing statement showing the distribution of any recovery.
A practical review checklist
- Find the signed agreement and identify the fee method, percentages, scope, expense treatment, and appeal or trial terms.
- Compare any AI or technology charge with the agreement and ask whether it is professional compensation, a disbursement, or ordinary overhead.
- If billed hourly, compare time entries with work actually performed. Do not assume that every AI task is free, but do not accept fictional hours or duplicate entries.
- If the fee is contingent or flat, do not convert it into an hourly fee after the fact without looking at the actual agreement and governing law. Consider reasonableness in context, including actual work, difficulty, result, risk, and applicable limits.
- Ask for a clear explanation of any proposed change and retain the response. Under ABA Model Rule 1.5 Comment [1], a fee-agreement modification should be reasonable under the circumstances when made, communicated to, and accepted by the client. A change to the basic nature of the fee arrangement or a significant increase in compensation, absent an unanticipated change in circumstances, is less likely to be reasonable. The governing state's adopted rule and law still control.
- If the answer does not resolve the concern, consult a lawyer who handles professional responsibility or fee disputes in the state where the matter is governed. A local bar referral service or the state bar’s fee-dispute program may be a starting point, if available.
Closing thought
AI can change how legal work is done. It does not erase the lawyer’s duties to charge a reasonable fee, follow the fee agreement, protect client information, and communicate as required. For a contingency fee, the right review is contextual: read the agreement, separate fees from expenses, ask how any AI charge is calculated, and check the rules that actually govern the representation.
Questions
Does ABA Formal Opinion 512 require a lawyer to lower every contingency percentage when using AI?
No. It says Rule 1.5’s reasonableness factors apply to contingent fees as well as other fee arrangements and discusses the possibility that AI-driven efficiency can affect whether a flat or contingent fee is reasonable. It does not set a required percentage reduction or an automatic discount for every matter.
Can a lawyer charge the same contingency percentage if AI saves time?
The ABA framework does not answer that with a categorical yes or no. The percentage and agreement must be evaluated under the applicable reasonableness standard and state law. Consider what the lawyer agreed to do, the work and risk involved, the result, the fee terms, and any statutory or court-imposed limits. A few automated steps do not by themselves establish that the overall fee is unreasonable.
Can my lawyer charge me separately for AI software?
Sometimes, but it depends on the tool, use, agreement, and governing rules. ABA Model Rule 1.5(b) calls for communicating the basis or rate of the fee and the expenses for which the client is responsible before or within a reasonable time after representation begins, preferably in writing. Formal Opinion 512 separately says that before charging for an AI tool, the lawyer must explain the basis, preferably in writing. The opinion distinguishes ordinary practice overhead from a potentially reasonable, matter-specific out-of-pocket expense. Ask for the contract language and a clear calculation before agreeing to a separate charge.
If a lawyer uses AI on an hourly matter, can the lawyer bill the time AI would otherwise have taken?
Under Formal Opinion 512’s discussion of the ABA Model Rules, a lawyer who bills hourly must record actual time spent, not hypothetical time that would have been spent without AI. Actual time spent prompting, reviewing, correcting, and applying AI output may be billable if it was genuinely spent on the matter and the charge is reasonable under the agreement and local rules.
Do I have a right to be told whenever my lawyer uses AI?
Not necessarily under the ABA Model Rules in every situation. Opinion 512 says the facts matter. Disclosure or consultation may be required when confidentiality rules require informed consent, when AI affects the fee, when the client asks, when the engagement terms require it, or when the use is significant to a decision or the client’s reasonable expectations. State rules and court requirements may differ.
This article uses the ABA Model Rules and ABA guidance as a national reference point, not state-specific legal advice. ABA model rules and opinions are not automatically binding in every jurisdiction. Check the current law, rules, and fee agreement that govern the representation with qualified local counsel.
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