Should Law Firms Use Cash Or Accrual Accounting?

Your firm bills a client $8,000 for retainer work in March, but the payment does not land until April. Which month does that revenue belong to? The answer depends on which accounting method your firm uses, and working through cash or accrual accounting for law firms is one of the first real financial decisions a growing practice has to make.

What Is the Difference Between Cash and Accrual Accounting for a Law Firm?

Cash accounting records revenue and expenses when money changes hands. Accrual accounting records them when they are earned or incurred, regardless of when the cash arrives. For a firm juggling retainers, contingency matters, and invoices with 30 or 60 day terms, that distinction changes how your books read from month to month.

How Does Each Method Treat Client Retainers and Unpaid Invoices?

Say your firm sends a $5,000 invoice in June for work already completed, and the client pays in July. Under cash accounting, that $5,000 shows up as July revenue, since that is when the money arrives. Under accrual accounting, it counts as June revenue and creates a $5,000 receivable, and the July payment simply clears that receivable rather than adding new revenue.

Are Law Firms Actually Required to Use Accrual Accounting?

No, not automatically. Under current IRS rules, most professional service businesses, including law firms, can generally use cash accounting no matter how much revenue they bring in, as long as the firm does not carry inventory. It is easy to assume growth eventually forces a switch. On revenue size alone, it does not.

That said, this treatment has faced repeated legislative challenges. Congress has floated proposals more than once to strip the cash method exemption from law firms and other personal service businesses, and the American Bar Association has consistently opposed those proposals, arguing they would force firms to pay tax on income before they ever collect it. None have passed so far, but the exemption is worth confirming with a tax advisor rather than assuming it is permanent.

What Could Cause a Law Firm to Lose Its Cash Accounting Eligibility?

Two things matter most here. If your firm carries meaningful inventory, which is rare for legal practices but not unheard of, that can affect eligibility. Entity structure matters too: C corporations face a separate gross receipts test capped at a threshold the IRS adjusts for inflation each year, currently $32 million for 2026, though most law firms are structured as partnerships or S corporations and fall outside that test entirely. A tax advisor can confirm how your specific entity type is treated.

Which Method Fits Your Firm’s Size and Growth Stage?

Solo and small firms with straightforward billing, a handful of matters, and simple retainer arrangements do fine on cash accounting. It is simpler to maintain and easier for whoever manages the books to keep current. Firms pursuing outside financing, weighing a merger, or wanting real visibility into profitability by practice area tend to benefit from what accrual accounting shows them.

When Does a Growing Firm Typically Outgrow Cash Accounting?

The trigger is rarely size on its own. It is usually a specific event: applying for a line of credit, bringing on new partners who want clear profitability numbers before buying in, or wanting attorney or practice area level data to guide staffing and business development decisions. Any of these can make accrual accounting’s fuller picture worth the added complexity.

How Does Your Accounting Method Interact With Trust Accounting Compliance?

Your choice between cash and accrual accounting has no bearing on your trust accounting obligations. IOLTA rules and three way reconciliation apply to your trust accounts regardless of which method you use for your operating books. This trips up more firm owners than you would expect, since switching accounting methods can feel like it should change how client funds are tracked. It does not. Trust account compliance runs on its own rules, separate from whatever method governs your revenue and expense recognition.

How Do You Move From Cash to Accrual Accounting Without Disrupting Your Firm?

A clean switch starts with evaluating your current financial processes to find what your books are missing today, usually a proper accounts receivable and payable structure. From there, your chart of accounts needs updating to support accrual level detail, and whoever manages your books needs training before it goes live. Most firms time the actual switch to a clean period, like the start of a new fiscal year, rather than mid-stream.

What Should You Expect During the Transition Period?

Expect some temporary bumps. Your financial reports may look different for a month or two as receivables and payables work into the system, and whoever handles your books will have a short learning curve with the new entries. Neither is a sign anything went wrong, it is just part of the shift.

This is exactly the kind of transition Milestone handles for law firms every day. Milestone’s law firm accounting team offers Cash to Accrual conversion as a named service, built alongside its broader virtual accounting services for legal practices, so you are not left updating the chart of accounts and retraining staff on your own. Milestone also brings the law firm specific expertise a generalist bookkeeper often lacks, from IOLTA trust accounting to matter based reporting to partner draws. If your firm is weighing this switch, talk to Milestone’s law firm accounting team about what the transition would look like for your books.