Quick Insights
- Most small law firms qualify for cash accounting — the IRS only requires accrual for C corporations and certain partnerships with average gross receipts above $32 million under IRC Section 448.
- Cash accounting is simpler and gives you more control over when you recognize income, which matters a lot for year-end tax planning.
- The choice isn't permanent, but switching later requires IRS approval through Form 3115 and some planning — so it's worth getting right the first time.
For a small law firm with a handful of partners, the accounting method question usually comes up once: when you're getting started, or when your current setup stops feeling right. It doesn't require a deep dive into tax code. It mostly comes down to how your firm bills, how your clients pay, and how much financial visibility you actually need.
Here's how to think through it.
Cash Basis Accounting: Simple and Tax-Friendly
Cash basis accounting records transactions when money changes hands. Revenue hits your books when clients pay, not when you send the invoice. Expenses are deducted when you pay them, not when you incur them.
For most small firms, this is the right default. It's straightforward, easy to manage without dedicated accounting staff, and keeps your reported income aligned with what's actually in your bank account.
Where cash accounting works well:
- Firms that bill hourly with predictable payment timelines
- Practices where most clients pay within 30–60 days
- Partners who want clean, simple books without tracking outstanding receivables
- Year-end tax planning: you can delay sending invoices until January or prepay December expenses to manage taxable income
Where it creates problems: If your firm carries large matters that generate fees in one month and collect in another, cash accounting makes your financials lumpy and hard to read. A firm that settles a big case in December but doesn't collect until February will show a weak December and an inflated February — neither reflects what actually happened.
Accrual Accounting: More Accurate, More Work
Accrual accounting recognizes revenue when it's earned and expenses when they're incurred, regardless of when cash moves. You record income when you complete the work, not when the client pays.
The result is a cleaner picture of how the firm is actually performing month to month. It matches revenue to the work that generated it, which makes partner compensation conversations easier and financial planning more reliable.
Where accrual accounting works well:
- Firms handling contingency cases or matters that span several months
- Practices with retainer arrangements where work and billing don't always align
- Partners who want to track matter profitability or spot collection problems early
- Firms with more complex financials where management decisions depend on accurate data
The tradeoff is overhead. You'll need to track accounts receivable, work in progress, and accrued expenses — which means more bookkeeping time and, typically, better accounting software. For a small professional services firm, that added complexity isn't always worth it.
What the IRS Actually Requires
For most small law firms, there's no federal mandate on which method to use. The IRS restricts cash accounting under IRC Section 448 only for C corporations and partnerships that include a C corporation as a partner — and only when average gross receipts exceed the annual threshold. As of this year, that threshold is $32 million: above that, you have to use accrual accounting.
If your firm is structured as a partnership, LLC, or S corporation — which covers the vast majority of small practices — you're free to use cash accounting regardless of revenue. The choice is yours to make based on what actually works for how your firm operates.
Which Method Fits Your Firm
Cash accounting is probably the right fit if:
- Your billing is mostly hourly and clients pay on a regular schedule
- You don't carry much unbilled work at any given time
- You want to keep your law firm's bookkeeping simple and manageable in-house
- Year-end tax flexibility matters to how you and your partners plan
Accrual is worth considering if:
- You handle contingency cases, complex retainers, or long-running matters
- Partners have started asking questions that your current financials can't answer clearly
- You've had collection issues and want better visibility into aging receivables
- You're planning to bring on associates or expand and need cleaner data to make those decisions
One thing that's easy to overlook: trust account management. Client funds in trust aren't firm income until earned, but tracking them alongside firm finances adds administrative complexity either way. High-volume practices sometimes find that one method creates less friction than the other depending on how their billing and collections work.
If You Ever Need to Switch
The IRS expects consistency — you can't move between methods year to year. Switching requires filing Form 3115 and getting approval, which is a process but not an obstacle if you plan ahead. The bigger consideration is timing: if you've been on cash accounting for years and have built up significant receivables, switching can pull that income into the current tax year all at once. Worth discussing with your accountant before you decide to make the move.
The Right Method Is the One That Matches How You Actually Run Your Firm
For most small law firms, cash accounting is the right starting point. It's simpler, it works, and it gives you useful tax planning flexibility. If your practice gets more complex — more partners, more contingency work, more financial decisions that require better data — accrual may start to make more sense.
Not sure which applies to your situation? Talk to Revonary. We work with law firms on these decisions and can help you choose a setup that fits how your firm actually operates.
