How to invoice a retainer client

In short: To invoice a retainer client, agree what the monthly fee buys and whether you bill in advance or in arrears, then send the same invoice on the same date every month with the period clearly named. Billing in advance is the norm for retainers, because the point of a retainer is that the client has reserved your time.

A retainer is the best kind of freelance income: predictable, renewing, and it removes the monthly scramble for the next project. The invoicing should be just as boring, and once it is set up it very nearly is.

The example here: €1,200 a month for ongoing design support, billed on the 1st, covering that month, due in 14 days. Same amount, same date, twelve times a year.

For invoicing fundamentals, start with how to invoice a client as a freelancer.

What is a retainer, and what is the client actually buying?

Worth settling before you write a single invoice, because it decides everything else.

• A block of time. “Up to 20 hours a month.” The client is buying availability, and unused hours usually expire.
• A defined set of deliverables. “Four social posts and one newsletter a month.” Easier to invoice and easier to defend, because done is visible.
• Access and priority. “First call on my diary, 48-hour turnaround.” The client is paying to jump the queue, and what they use varies month to month.

The most common disputes on retainers come from nobody writing down which of these it is. Put it in the agreement, and put a short version of it on every invoice.

Should you invoice a retainer in advance or in arrears?

In advance is the norm, and it is the one to push for. The client is reserving your capacity for the coming month, so they pay for it at the start of that month. It also means you aren’t funding the relationship, and a client who stops paying stops the work before you have already done it.

In arrears makes sense when the monthly amount genuinely varies, for example a base fee plus whatever extra work was approved. Some larger organisations will also insist on it as policy.

Either way, name the period on the invoice. “Retainer, October 2026” is unambiguous. “Monthly retainer” is not, and it will eventually cause an argument about whether September was paid.

How to invoice a retainer client, step by step

1. Agree the fee, the scope and the billing date in writing, plus how much notice either side gives to end it.
2. Pick a fixed date and stick to it. The 1st is the usual choice for advance billing, the last working day for arrears.
3. Name the period on every invoice. “Design retainer, October 2026.”
4. Describe what it covers in one line, so the invoice makes sense on its own a year later.
5. List any extra work separately, below the retainer line, with its own description.
6. Add VAT if it applies, and set the due date from the client’s agreed terms.
7. Send it on the same date every month, without waiting to be asked.

What to put on a retainer invoice

Keep the base simple and itemise anything that is not the base:

Two habits that prevent most retainer friction. Put the scope on the line, so “up to 20 hours” is visible on the document the client’s finance team files. And don’t bury extra work inside the retainer figure, because a fee that silently changed from €1,200 to €1,500 gets queried, while a separate line that says what it was rarely does.

How do you handle unused hours?

Decide the policy once, write it into the agreement, and then apply it without negotiating monthly.

• Use it or lose it. The cleanest, and standard for availability-based retainers. The client is buying your reserved time, not a bank of hours.
• Limited rollover. Unused hours carry into the next month only, then expire. Fairer-feeling, and it stops a client accumulating a large unusable balance.
• No rollover, but flexible scope. Hours are fixed, what you spend them on is not.

One honest note on tooling. Tally Crow does not track time: there is no timer and no hours counter. You track hours however you already do, in a spreadsheet or a dedicated timer app, and the retainer invoice carries the agreed monthly fee. If you need time tracking built into the same tool, that is a fair reason to look elsewhere, and worth knowing before you set this up.

If you genuinely owe a client money back, for example a month where you could not deliver, do not edit the invoice you already sent. Issue a credit note against it. Unapplied credit in the same currency can then be deducted on the following month’s invoice, which is exactly the shape of a retainer adjustment.

How to stop raising it by hand every month

A retainer is the same invoice twelve times, which is precisely the kind of task that gets forgotten in a busy month, and a retainer invoice sent on the 9th instead of the 1st quietly retrains the client to pay late.

Tally Crow has recurring invoices on the Pro plan: you set up the template and the cadence, and it generates the invoice for you on schedule. One deliberate detail worth knowing: the generated invoice is not emailed to your client automatically. You are notified to review and send it. That is a design choice rather than a limitation, because a retainer invoice often needs a line adding for extra work, and an automatic send would post the wrong figure before you noticed.

Recurring invoices are Pro (€14.99/mo, €149.90/year). Free and Basic do not include them, so on those plans you raise the monthly invoice yourself, which is two minutes with a saved client. See pricing for what is on each plan.

What happens when the scope changes?

Retainers drift. The client asks for a little more each month, and a year later you are doing half again as much work for the same fee. That is a pricing conversation, not an invoicing one, but the invoice is where it becomes visible.

This is the strongest argument for listing extra work as separate lines. After three months of “additional work approved” lines, you have the evidence for the conversation, in the client’s own approvals, rather than a feeling that you are doing too much.

When you do change the fee, change it from a clean month boundary, confirm it in writing, and let the first invoice at the new rate say so on the line.

Predictable income, predictable admin

The whole point of a retainer is that it removes uncertainty, and the invoicing should do the same. The same amount, the same date, the period named, extra work itemised, and a credit note when something needs adjusting. Tally Crow handles the numbering, VAT and currency, keeps each client’s terms, and on Pro raises the recurring invoice for you to review. Starting free, with 2 invoices a month and no credit card. See features.