How to Write an Invoice for Retainer Agreements

1. What is a Retainer?

A retainer is an advance payment made by a client to secure a freelancer's availability for a specific number of monthly hours.

2. Invoicing Upfront vs. Post-Work

Retainers are typically billed upfront at the start of the month (e.g. invoiced on the 1st, due upon receipt) to secure resource reserves.

3. Reconciling Rollover Hours

Clearly state if unused hours roll over to the next month or expire. Most freelancers write contracts where hours expire to ensure predictable schedules.