Retainer Invoice Template

• Business and Invoice details: your business name, address and phone or email; the invoice number, invoice date, payment terms, due date and the retainer period the invoice covers.
• Bill to (client): the company, an "Attention" line for the person who handles the bill, the address and an email.
• Retainer terms: the monthly retainer, the included hours, the overage rate and what happens to unused hours, printed on every invoice so the client sees the terms each time.
• Retainer: the retainer fee for the period, with the period and included hours in the "Details" column, and a "Retainer subtotal".
• Overage hours: hours over the included amount, with the period they were worked in, the hours used, the quantity and the hourly rate, and an "Overage subtotal".
• Totals: "Subtotal", "Sales tax, if applicable", "Total", "Less: unused retainer credit, if any" and "Amount due".
• How to pay: the methods you accept, placeholders for your account details and a payment reference.
• Retainer notes: when the retainer and overage are billed, and the hours used in the previous period.

The sample is a bookkeeping firm's December invoice to a cafe client. The retainer is 2,400.00 for Dec 1-31, 2026, including 20 hours. In November the client used 23.5 hours, so 3.5 overage hours at 120.00 an hour add 420.00. The subtotal and total are 2,820.00 with sales tax at 0%. The unused retainer credit is 0.00, because the sample terms say unused hours expire at the end of each period, which leaves 2,820.00 due by Dec 16, 2026 on Net 15 terms. Every name, rate and amount is a placeholder, not a market rate.

The PDF is a blank form to print and fill in by hand. The Word and Excel files have the same layout with the sample values to type over.

A monthly retainer billed at the start of the period is paid before the work for that period is done. In accrual accounting, money received for work you haven't yet provided isn't revenue yet: OpenStax's accounting text says that until the customer is provided the product or service, "a liability exists" (unearned or deferred revenue), and it becomes revenue as the work is delivered (OpenStax, Principles of Accounting). In practice, record December's retainer as unearned when it's paid and recognize it as you provide December's work. See what is deferred revenue for more, and ask your accountant how this applies to your books.

Lawyers. If you're a lawyer, check the trust account rules where you're licensed before you treat a retainer as earned. As a model, ABA Model Rule 1.15(c) says a lawyer deposits legal fees and expenses paid in advance into a client trust account, to be withdrawn only as fees are earned or expenses incurred (ABA Model Rule 1.15). The Model Rules aren't law in themselves; the rules that bind you are the ones in force where you're licensed. The lawyer invoice is built for applying an advance against time entries; this template doesn't keep trust records.

1. Enter your business details, the invoice number, the invoice date, the payment terms, the due date and the retainer period.
2. Enter the client under "Bill to (client)", then the retainer terms: the monthly retainer, the included hours, the overage rate and your unused-hours terms.
3. On the "Monthly retainer" line, put the period and included hours in "Details", 1 month in "Qty" and the retainer fee in "Rate".
4. Under "Overage hours", enter the hours over the included amount for the earlier period, with that period and the hours used in "Details" and your overage rate in "Rate". If there was no overage, clear the quantity, or enter 0, and the line comes to nothing.
5. If your terms credit unused hours in money, type the credit on "Less: unused retainer credit, if any". Otherwise leave it at 0.00.
6. Edit the retainer notes and the payment details, then send the invoice and keep a copy.

In the Excel file, each line amount is Qty × Rate, and the section subtotals, the subtotal, the sales tax, the total and the amount due are formulas. The sales tax rate sits in its own cell, starting at 0%; "Total" is the subtotal plus tax, and "Amount due" is the total less the unused retainer credit, which you type. To leave out the tax, set its rate to 0%. To leave out the credit, set it to 0.00. Don't delete either row, because the totals refer to them. The overage section has one blank row; to add more lines, insert a row above that blank row and copy the amount formula into it, then check that the overage subtotal and the subtotal include it. In Word or on the PDF, work out the amounts and enter them.