Billing for AI-Assisted Legal Work in NJ: What RPC 1.5 Actually Permits — and Where Small Firms Get It Wrong

A solo attorney in Trenton drafts a demand letter in 22 minutes using an AI writing tool. It used to take her 90 minutes. She bills the client for 1.5 hours at her standard hourly rate.

Is that ethical?

It depends — and the answer is more nuanced than most NJ small firm attorneys realize. As AI continues to compress the time it takes to perform core legal tasks, the question of how to bill for that work has quietly become one of the most pressing practical ethics issues in solo and small firm practice. Yet it remains almost entirely undiscussed compared to the noise around confidentiality and disclosure.

Let's fix that.

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What RPC 1.5 Actually Says

New Jersey's RPC 1.5 requires that a lawyer's fee be reasonable. The rule sets out eight factors for assessing reasonableness, including the time and labor required, the skill needed, the customary fee in the community, and the results obtained.

None of those factors contemplate the tool used. A letter requiring skilled legal judgment doesn't become less valuable because it was produced faster. That's the intuitive argument for maintaining standard billing rates even when AI assists — and it's not wrong.

But here's the tension: RPC 1.5 also prohibits billing for time not actually spent, and billing a client for 90 minutes of work you completed in 22 minutes starts to look like a misrepresentation, not a value-based fee arrangement — especially if your engagement letter frames the billing as hourly.

The billing model you're operating under matters enormously.

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The Hourly Billing Problem

If you bill hourly and AI cuts your drafting time by 60%, billing your old hours for the same output is ethically shaky. You're not billing for value — you're billing for time you didn't spend. The NJSBA has not yet issued formal guidance specifically on AI billing practices, but the ABA's 2023 Formal Opinion 512 is instructive: it warns that lawyers may not bill a client for time not actually expended, and that AI-generated work product must be reviewed and supervised before billing for it at all.

The safest posture for hourly billers right now:

• Bill for the time you actually spend — including prompting, reviewing, editing, and supervising the AI output. That review time is real and billable.
• Do not mark up AI tool costs passed to clients without disclosure. Reasonable costs may be billable, but they should be disclosed in your engagement letter, just as you would handle filing fees or courier charges.
• Update your engagement letter to address how AI-assisted work is handled and how it affects billing. Silence is where disputes start.

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The Case for Value-Based Fees — and Why AI Accelerates the Shift

Here's the strategic opportunity most small firm attorneys are missing: AI is a natural forcing function toward flat-fee and value-based pricing.

If a client hires you to prepare a business contract and you charge a flat $1,200, nobody cares if you used AI to produce the first draft in 18 minutes. The client gets a well-reviewed, attorney-supervised agreement. You get a reasonable fee. RPC 1.5 is satisfied. Everyone wins.

The attorneys who will navigate AI billing most cleanly are those who move their practices — or at least specific practice areas — toward flat-fee or subscription-style arrangements. Family law intake packages, estate plan bundles, standard commercial lease reviews: these are all candidates. The time savings AI creates become margin, not an ethics problem.

This isn't hypothetical. Several NJ solo attorneys I've worked with have already restructured their residential real estate and simple estate planning work this way. They're more profitable, clients appreciate the pricing transparency, and the RPC 1.5 question essentially disappears.

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What to Do This Week

You don't need to overhaul your entire practice. Start here:

1. Audit one practice area where AI already saves you meaningful time. Quantify roughly how much.
2. Check your current engagement letter. Does it define what you're billing for? Does it address AI tools or cost pass-throughs? If not, update it.
3. If you bill hourly, establish a personal policy: bill for actual time spent, including review — not historical averages for tasks the AI now handles faster.
4. Consider a flat-fee pilot for one well-defined matter type. Price it at what the work is worth to the client, not what it used to cost you in hours.
5. Document your AI workflow for any matter you bill for. If a fee dispute ever arises, you want a clear record of what you did, what the tool did, and how you supervised the output.

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The Bottom Line

RPC 1.5 isn't a barrier to using AI — it's a prompt to rethink how you price your practice for a world where legal work gets done faster. The attorneys who treat that as a threat will keep billing uncomfortably for hours they didn't spend. The ones who treat it as an opportunity will restructure around value, capture the efficiency gains as profit, and never have to worry about whether their billing reflects reality.

The ethics question answers itself when the business model is right.