Bookkeeping for Law Firms: Trust Accounting & IOLTA, Done Right

Most small businesses can survive a messy month of books. A law firm can't — because some of the money in your accounts isn't yours. Client retainers, settlement funds, and advance-fee deposits are held in trust, and mishandling them — even by accident, even briefly — is one of the fastest ways to draw a bar complaint or an audit. This guide covers how law firm bookkeeping actually works: the two-account structure, the rules of trust accounting, the three-way reconciliation that keeps you compliant, and the mistakes that get good attorneys in trouble.

Why law firm bookkeeping is uniquely high-stakes

Every state bar has rules governing how attorneys handle client money, and they are strict, specific, and enforced. The core idea is simple: money that belongs to a client is not your money, and it has to be kept separate, tracked to the penny, and never borrowed — not even for a day, not even with every intention of paying it back. A shortfall in a trust account, however innocent, is treated as a serious ethics violation.

That's why law firm books are less about squeezing margins (like a restaurant) and more about compliance and provability. Your books have to be able to show, at any moment, exactly how much of the money in trust belongs to each client. Getting that right is the whole job.

The two-account structure: operating vs trust

Every law firm runs on (at least) two separate bank accounts:

• The operating account — the firm's own money. Earned fees, payroll, rent, software, and every normal business expense flow through here. This is where your profit and loss lives.
• The trust account (IOLTA) — client money the firm is holding but has not yet earned or disbursed. Unearned retainers, settlement proceeds, and filing-fee advances sit here until they're properly earned or paid out.

IOLTA stands for Interest on Lawyers' Trust Accounts. For pooled client funds that are too small or short-term to warrant their own account, the interest is remitted to a state program (usually funding legal aid) rather than to the firm or the client. Larger or longer-held sums may go in a separate client trust account instead. Either way, the bookkeeping principle is identical: it's not your money until you've earned it.

The cardinal rules of trust accounting

• Never commingle. Firm money and client money never mix. You don't pay the electric bill from trust, and you don't park operating cash in the IOLTA to earn interest.
• Never let a client's balance go negative. You can only ever disburse or draw against what that specific client has in trust. Using Client A's funds to cover Client B's shortfall — even temporarily — is a serious violation, and it's shockingly easy to do by accident if your books don't track balances per client.
• Track every client's balance individually. The trust account is one bank account, but inside it every client (and often every matter) has their own sub-ledger. The sum of all client sub-ledgers must always equal the bank balance.
• Move earned fees out promptly. Once you've earned a fee (per your engagement terms), transfer it from trust to operating with a clear record. Leaving earned money in trust is its own problem.

Three-way reconciliation: the thing that keeps you out of trouble

Ordinary businesses do a two-way bank reconciliation — books vs. bank statement. Law firms must do a three-way reconciliation of the trust account, and most bars require it monthly. Three numbers must all agree:

1. The trust bank-account balance  =  2. Your trust ledger balance  =  3. The sum of every individual client's trust sub-ledger.

When all three match, you can prove that every dollar in trust is accounted for and attributed to the right client. When they don't match, you've found a problem before the bar does — a bank fee that hit the trust account, a disbursement recorded against the wrong client, a deposit that never cleared. Three-way reconciliation is the single most important bookkeeping task a law firm performs, and it's the first thing a bar auditor asks to see.

Earned vs. unearned fees (getting retainers right)

When a client pays a retainer, that money is usually unearned — it goes into trust, and it stays the client's money until you do the work. As you bill against it, the earned portion moves to your operating account and becomes revenue. This matters for two reasons: it keeps you compliant (unearned money can't sit in operating), and it means your revenue is recognized when it's earned, not when the retainer arrives — a classic accrual distinction. Flat fees and true "earned on receipt" retainers work differently, and the exact treatment depends on your engagement letter and your state's rules, so this is worth getting a professional's eyes on.

The mistakes that trigger bar complaints

• Commingling — paying an operating expense out of trust, or vice versa.
• Negative client balances — disbursing more than a client has in trust, often invisibly.
• Skipping the monthly three-way reconciliation — the omission itself can be a violation, and it lets small errors compound.
• Letting bank or card fees hit the trust account — those are firm costs and must be covered by the firm, not netted out of client funds.
• No per-client ledger — treating trust as one big pool with no way to prove who owns what.

How Tides handles law firm books

Trust accounting rewards discipline and provability, and that's the kind of work we're built for. We set up your operating and IOLTA accounts cleanly, maintain a per-client trust sub-ledger, perform the monthly three-way reconciliation so you can always prove every dollar, and keep earned-fee transfers documented so nothing lingers where it shouldn't. On the operating side you get the same clean monthly financials any firm needs — see how we support professional-services firms, and the full picture in our complete guide to small business bookkeeping.

One important note: we handle the bookkeeping and reconciliation; we are not your compliance counsel, and the definitive rules are your state bar's. A good setup keeps you clean and makes any bar review painless — but the ethical responsibility for the trust account always stays with the attorney.

Frequently asked questions