Law Firm Invoice Template: 12 Sections and a Worked Monthly Bill Against a Trust Retainer

What a law firm invoice template has to do

A law firm invoice template is not a generic invoice with "legal services" typed on one line. A client reading a legal bill wants to know three things: what was done on their matter, who did it at what rate, and how much of their retainer is left. A bill that answers those on one page gets paid. A bill that says "professional services, $3,182.50" gets a phone call, a request for detail, and a payment that arrives a month late.

The rules behind the bill matter too. Under Rule 1.5(b), which most states adopt from the ABA Model Rules, the scope of the representation and "the basis or rate of the fee and expenses" have to be communicated to the client, preferably in writing, and any change in the rate has to be communicated as well (Idaho Rules of Professional Conduct, Rule 1.5 (follows ABA Model Rule 1.5), checked October 31, 2026). The invoice is where the client checks that the rate on the engagement letter is the rate they are paying. Your own state's version of the rule, and its trust-account rules, are the ones that bind you, so check them.

The fill-in template

Copy these sections, in this order. Each one answers a question a client will otherwise ask by email.

1. Firm block. Firm name, address, phone, billing email, and your tax ID if clients need it for their books.
2. Client and matter. Client name, matter name and matter number. One invoice per matter, never several matters blended into one total.
3. Invoice number, date and billing period. "Services from October 1 to October 31." The period is what lets a client match the bill to what they remember happening.
4. Fee basis, restated. One line: "Hourly per engagement letter dated March 4: partner $350, associate $225, paralegal $125." For flat-fee or contingent matters, say so here instead.
5. Time entries. Date, timekeeper, a plain-English description, hours in tenths, rate, amount. "Draft and file motion to compel; review opposing counsel's response" is a description. "Work on file" is not.
6. Fees subtotal by timekeeper. Hours and amount per person, so the client sees who did the work.
7. Expenses. Filing fees, service of process, copies, expert or court reporter costs, each on its own line, and whether they are passed through at cost.
8. Total this invoice.
9. Trust account activity. Opening trust balance, amount applied to this invoice, closing trust balance, and whether the client needs to replenish the retainer.
10. Prior balance and payments received. What was outstanding, what came in, and on which date.
11. Balance due and due date. One number, in bold.
12. How to pay. Card or bank link, check address, and which account the payment goes into. Payments that replenish a retainer go into trust, payments for earned fees into operating; the invoice should say which.

Worked example: one month on a litigation matter

These are example rates and hours for illustration, not market rates. The structure is the point: the client holds a $5,000 retainer in trust, and the firm bills monthly against it.

Two things in this example are worth copying. First, the trust line. The client sees that their $5,000 retainer covered $3,774.50 of the bill and that $1,225.50 is left, so the replenishment request that follows is no surprise. Second, the split between fees and expenses. Clients push back on fees far more than on a filing fee they can see on the court's own schedule, so keeping expenses on their own lines saves the argument.

The 13.7 hours on this invoice only pay if they were recorded. Time that was worked but never entered is the most common leak in a small firm's billing, ahead of write-downs and late payments. Our free law firm billable hours calculator shows how much revenue sits between hours worked, hours billed and hours collected.

Flat-fee and contingent matters need different invoices

For a flat-fee matter, the invoice lists the fee, the milestone that earned it (for example, "estate plan documents signed"), and any expenses billed on top. Time entries are optional, though some firms include them so the client sees the work behind the flat number.

A contingent matter usually has no monthly invoice at all. What it needs is the closing statement: at the end of a contingent fee matter, the lawyer gives the client "a written statement stating the outcome of the matter and, if there is a recovery, showing the remittance to the client and the method of its determination" (Idaho Rules of Professional Conduct, Rule 1.5 (follows ABA Model Rule 1.5), checked October 31, 2026). In practice that is gross recovery, the fee percentage and amount, each expense, and the net to the client.

Getting paid faster

• Send on the same day every month. Clients budget for a bill that arrives on the 1st. One that arrives on the 19th competes with everything else.
• Put the pay link on the invoice. A card or bank link on the first page removes the step where the client has to find a checkbook.
• Follow up on day 15 and day 30. A short, polite reminder that repeats the balance and the pay link. Most late legal bills are forgotten, not disputed.
• Ask for the replenishment before the trust runs dry. When the trust balance drops below one month's typical billing, the invoice should say so.

Where Unmanually fits

Unmanually is a 24/7 AI Office Manager you run by voice from your phone. For a small firm, it answers intake calls and books consultations, and it does the follow-up on invoices: the day-15 and day-30 reminders, the replenishment request when a trust balance runs low, and the "did you get my invoice?" questions. You approve before anything goes out. The billing judgment, the write-downs and anything touching the trust account itself stay with you. See Unmanually for law firms.