A monthly retainer is a contract where your customer pays a fixed amount each month for agreed services. At the end of the month you may need to show the work you did against it, charge for any overage, or roll over what wasn't used. Here is the approach we suggest: one project per month, with the retainer amount as its budget.
First choose how to bill the retainer itself:
- The same amount every month, however much is used: a recurring invoice.
- Paid in advance and held as credit that your invoices draw on: a retainer subscription.
- Other ways to take money up front: see collecting advance payments.
Set up the month's project
Create a project for the month, such as "Fernleaf Media retainer – October 2026".
In its settings, on the Billing & Budget tab, set the Budget Type to Total Project Fees with the monthly retainer amount. Set the Billing Method to Not Billable, because the tracked time won't be added to an invoice. See entering a project budget.On the Members tab, add the team and set each person's Cost Rate to the rate at which their time uses up the retainer. See cost and billable rates.
Add a task for each agreed deliverable, so the team tracks time against it and you can share the details with the customer.
Send the retainer invoice. Once it's paid, the retainer is active.
To see the invoice in the project's figures, switch on Enable Project Invoice Link in Settings › Invoice & Bill Settings and link the invoice lines to the project. The Project Summary and Project Profitability reports count linked lines on regular invoices, not on retainer invoices.To budget expenses too, set a Budget Amount for each expense category on the Categories tab.
Creating projects needs the Administrator, Portfolio Manager or Project Manager role. Invoicing needs Administrator or Finance Manager.
Follow the retainer during the month
Your team tracks time and expenses on the month's project as they deliver the work.
Check how the retainer is doing in the Project Summary report. For a Total Project Fees project, its budget panel shows the Total Budget, the Cost so far and the Margin: what's left, or how far you're over. Time counts at cost rates, and expenses and bills count against the budget by default.
Give every monthly project of the same retainer the same project category. You can then run the Project Dashboard report filtered by Project Categories, to see the budget, spent and remaining amounts of all its months together.
Close the month
- Share the work done with the customer using the Timesheet Details report or the Task List report.
- If you went over, add the overage to next month's invoice.
- If money is left over and your contract rolls it over, raise next month's project budget by that amount.