How To Accept Payments For A Law Firm

A law firm holds client money before it earns any of it, and the rules governing that money are stricter than anything else in this series. Trust accounting comes before payment convenience, always. Here is how a firm should structure collection inside that framework.

Figures current to July 28, 2026 and rechecked each quarter.

The trust accounting frame

Advance fees and retainers belong to the client until earned, and applicable professional conduct rules govern which account they sit in, how they are reconciled, when earned amounts may be transferred, and who bears payment processing costs. That last point matters practically: a processing fee deducted from a trust deposit can create a shortfall that is itself a violation, which is why firms accepting cards need a processor that can route fees to the operating account rather than the trust account. Confirm the rules that bind your licence rather than adopting another firm's arrangement.

By the numbers (July 28, 2026)

Square prices this lane at 3.3% + 30¢ online or on a card-paid invoice in 2026. A $5,000 retainer replenishment costs $165 to process, against $10.00 on ACH, where the 1% rate caps at $10, saving $155. Where the rules permit card replenishment, the processor must route fees to operating rather than trust, which is a configuration question worth resolving before the first charge.

How law firm money actually arrives

Four flows. Retainers and advance fees held in trust and drawn down as work is billed. Hourly billing against those balances, invoiced monthly with detail. Flat fees for defined matters, which are increasingly common and simpler to administer. And contingency arrangements in some practice areas, where the fee arrives at resolution and the firm carries the case in the meantime.

Evergreen retainers and replenishment

A retainer that replenishes when the balance falls below a stated floor removes most of a firm's collection problem, because the money is there before the work is billed. Set the threshold and replenishment amount in the engagement letter, agree the payment method at signing, and notify before each replenishment. Firms billing monthly in arrears spend partner and staff time chasing invoices, which is the most expensive collections function a business can operate, and the clients who pay slowest are rarely the ones a firm wants to keep.

Flat fees, which clients increasingly prefer

Defined matters price cleanly as flat fees: formations, wills, standard agreements, uncontested filings, and compliance work. Clients prefer knowing the cost, and the firm avoids writing off time on matters that took longer than the client expected to pay for. How a flat fee is treated for trust purposes, whether it may be deposited to operating on receipt or must be held until earned, depends on how it is characterised and on the rules in your jurisdiction, which is worth getting right at the outset rather than after a bar complaint.

Payment plans, cards, and collection

Where a client needs to pay over time, document it: amount, schedule, method, and what happens if payments stop. Card acceptance genuinely helps a firm get paid, particularly on smaller matters and consumer-facing practice areas, and the convenience often outweighs the fee. What is not acceptable is an informal arrangement that becomes a collection problem against a former client, since suing a client for fees invites a counterclaim more often than it recovers money, and firms that structure payment properly rarely find themselves considering it.

Sources

• NerdWallet — Square Fees: Calculator and Pricing for 2026
• Swipesum — Square Fees Explained 2026 (verified against Square's published pricing)

What people ask me

What governs how a law firm holds retainers?

Professional conduct rules covering which account funds sit in, how they are reconciled, when earned amounts transfer, and who bears processing costs.

Why do processing fees matter for trust accounts?

A fee deducted from a trust deposit can create a shortfall that is itself a violation, so firms need a processor that routes fees to the operating account.

What is an evergreen retainer?

A trust balance that replenishes when it falls below a stated floor, so funds are present before work is billed, removing most of the collection problem.

How should flat fees be treated?

Depends on characterisation and jurisdiction: whether they may go to operating on receipt or must be held until earned is worth resolving at the outset.

Should firms offer payment plans?

Yes, documented with amount, schedule, method, and what happens if payments stop, since informal arrangements become collection problems that invite counterclaims.

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