Retainers: how to bill a client the same amount every month

A client likes your work and wants you every month. You agree a fixed monthly amount and shake hands on it. By the third month they send twice as many requests as in the first. By the fifth they skip a month because “it was quiet”. Neither of you is acting in bad faith. You only agreed the amount, and a retainer is the amount plus the rules around it.

What a retainer is

A retainer is a fixed amount a client pays each period, usually each month, for ongoing work. It comes in two forms:

• For a set of work. The same tasks each month: the bookkeeping, the social posts, the site maintenance.
• For your time. A number of hours kept free for the client, used for whatever they need.

Either way the client gets a known cost and a place in your calendar, and you get income you can plan around. It is not the same as a deposit, which is paid once against one job. See deposit invoices.

Seven things to agree in writing first

One page is enough. An email the client replies “agreed” to is better than a long contract nobody signed.

Invoice at the start of the month

A retainer pays for you being available, so bill it before the month begins, not after it ends. Invoice on the same day every month, with a short due date. Seven days is common. If you bill at the end of the month with 30 days to pay, you have worked two months before the first payment arrives. See invoice payment terms.

Name the month on every invoice

Twelve invoices for the same amount to the same client are easy to confuse. Put the month in the description: “Marketing retainer, November 2026”. When a payment arrives you both know which month it is for, and when one is missed you can point to it by name. The mechanics of sending the same invoice on a schedule are in recurring invoices.

Extra work goes on its own invoice

Keep the retainer invoice the same every month. When the client asks for more than is included, say so before you start: “This is outside the retainer. It would be about six hours at €85. Shall I go ahead?” Then bill it separately, or as a clearly named extra line. If the extras hide inside the retainer, the retainer quietly grows and the price does not.

If you bill by time, send a short note with each invoice: hours included, hours used. It takes five minutes and prevents most arguments about value.

Changing the price

• Give notice in writing, at least as long as your agreement says.
• Name the month the new amount starts from, so no invoice already sent changes.
• Give the reason in a sentence: more work, a yearly review, higher costs.

For example: “From January 2027 the retainer will be €1,650 a month. The invoices for November and December stay at €1,500.”

Pauses and quiet months

A retainer that the client can skip whenever work is light is not a retainer. It is hourly work with a fixed rate. Decide in advance what a pause is: how much notice, how long it can last, and whether you keep the client's place. If a month is paused, skip that month's invoice. Do not send it late once work starts again.

When a month goes unpaid

Because you bill ahead, you find out early. Send a reminder the day after the due date. If the next invoice is due and the last is still open, say that work stops until it is settled, and then stop. See payment reminder messages and, for the picture across several months, a statement of account.

The short version

• A retainer is a fixed monthly amount plus the rules around it.
• Agree what is included, unused time, the rate for extras, the invoice day, notice and price reviews, in writing.
• Invoice at the start of the month, on the same day, with a short due date.
• Name the month on every invoice, and bill extra work separately.
• Change the price from a named month, with notice.