The short answer: a marketing agency's bookkeeping needs to separate retainer revenue from project revenue, track work in progress (WIP) for project work the same way any professional services firm would, and keep clean, consistent records for the freelance and contractor network most agencies rely on to deliver client work. Blend all of this into one revenue line and one expense category, and an agency that feels genuinely busy can be quietly running several client relationships at a loss without anyone noticing until cash gets tight.
Key takeaways
- Blending retainer and project revenue into one number is the single most common reason a marketing agency cannot tell which clients are actually profitable.
- Retainer scope creep is the quiet margin killer in agency work, a retainer that was profitable at signing can become a loss leader within a year without anyone noticing.
- WIP for an agency looks different to a law firm's WIP, but the underlying principle, value created but not yet billed, is identical.
- Contractor and freelancer network payments need clean, consistent records, since agencies are frequently reviewed on exactly this kind of arrangement.
Retainer vs Project Revenue: Why Blending Hides the Truth
A marketing agency typically runs a mix of retainer clients (a fixed monthly fee for ongoing work) and project clients (billed against a specific campaign, website build, or brand project). Blended into one revenue number, a strong retainer base can make the whole agency look consistently profitable while individual projects, or individual retainers that have quietly grown in scope without a fee review, are actually running at a loss underneath that smooth average.
| Revenue type | How it should be tracked | What blending it with the other hides |
|---|---|---|
| Retainer | Separate income account, hours delivered tracked against the fee monthly | Scope creep that has made the retainer unprofitable without anyone noticing |
| Project (fixed scope) | Tracked against the original quote and actual hours or costs incurred | Underquoting at the proposal stage, repeated across similar future projects |
| Pass-through costs (media spend, stock photography, tools) | Tracked separately, marked up or billed at cost depending on the agency's model | Whether pass-through costs are genuinely being recovered or quietly absorbed |
Retainer Scope Creep: The Quiet Margin Killer
A retainer that was fairly priced at signing can become genuinely unprofitable within a year as the client's expectations grow, more channels, more reporting, more ad hoc requests, without the fee ever being revisited. The only reliable defence against this is the same discipline used across every professional services vertical: logging time against the retainer and comparing actual hours delivered to what the fee can sustainably cover, then having a proactive scope or fee conversation with the client before the relationship becomes resentful on the agency's side.
| Retainer health signal | What it suggests | Action |
|---|---|---|
| Hours delivered consistently under budget | Retainer is priced well, possibly room to take on more scope | Consider adding value or reviewing whether the fee could be adjusted fairly either way |
| Hours delivered consistently at or near budget | Retainer is fairly priced for current scope | Monitor, no action needed unless scope expands |
| Hours delivered consistently over budget | Scope has grown beyond what the fee covers | Proactive conversation with the client before resentment builds on the agency's side |
See Which of Your Retainers Are Actually Still Profitable
We set up retainer and project revenue tracking so you can see real margin by client, not just a healthy-looking agency total.
Book a Free 20-Minute CallWIP for an Agency: The Same Principle, a Different Shape
Work in progress for a marketing agency looks a little different to a law firm's WIP, it might be a campaign that has been built and launched but not yet invoiced, or a brand project at the halfway milestone, but the underlying principle is identical: value has been created through the team's time and is not yet reflected in revenue. An agency that only recognises revenue when an invoice goes out, with no visibility into WIP in between, is making the same mistake every professional services firm makes when it skips this step, it just looks slightly different in the details.
The Contractor and Freelancer Network
Most agencies rely on a network of freelance designers, copywriters, developers and specialists to deliver client work without carrying every skill set as a full-time employee. This is a completely normal and sensible way to run an agency, but it needs the same clean, consistent record-keeping any contractor relationship needs: clear invoicing from each freelancer, consistent payment terms, and genuine independence in how the work is delivered (own equipment, own methods, ability to work for other clients). Revenue offices have reviewed contractor arrangements across several sectors in recent years, and agencies with a large, loosely documented freelancer network are a natural area of focus.
Pass-Through Costs: Media Spend and Third-Party Tools
| Pass-through cost | Typical handling | What to check in the books |
|---|---|---|
| Media spend (Google Ads, Meta Ads budget) | Often billed to the client at cost, or with a management fee on top | Client media spend should sit as a pass-through, not blended into the agency's own advertising expense |
| Licensed stock, fonts, premium tools | Sometimes absorbed, sometimes rebilled | Decide deliberately whether these are absorbed into overheads or recovered per client, and apply it consistently |
| Subcontracted specialist work (video, animation) | Usually rebilled to the client, sometimes with a margin | Track cost and rebilled amount separately to see the actual margin on subcontracted work |
The specific policy an agency chooses for each of these, absorb the cost, rebill at cost, or rebill with a margin, matters less than applying it consistently and having the books actually show which approach is in use for each client. Inconsistency here is what makes one client relationship quietly more profitable than another for reasons that have nothing to do with the work itself.
Xero Setup for an Agency
A clean chart of accounts separates retainer income, project income, and pass-through costs (media spend, licensed stock, third-party tools billed to clients) into their own accounts. Tracking categories by account manager or team lead, the same pattern used across every other professional services vertical, make it possible to see which team members and which client relationships are genuinely driving profit once WIP and retainer data are both visible.
Utilisation Across an Agency Team
The same utilisation principle used across every professional services vertical applies to an agency team: what share of each team member's available hours are actually billable, across both retainer and project work combined. An agency running high utilisation across account managers, designers and strategists has genuine capacity data to justify a new hire or a rate increase. One running low utilisation has a pipeline, delivery efficiency, or scoping problem that another hire will not solve, and may well make worse by adding payroll cost without adding proportional billable capacity.
Common Mistakes That Erode Agency Margin
- Retainer and project revenue blended, hiding which relationships are actually profitable
- No WIP visibility, meaning profitability is only ever seen in hindsight
- Retainer scope creep never triggering a fee conversation, because nobody is tracking hours against the fee
- Pass-through costs absorbed rather than recovered, quietly reducing margin on every campaign
- Freelancer network records too thin to support genuine contractor classification if ever reviewed
What to Ask a Bookkeeper Before Hiring Them for Your Agency
- "How would you separate our retainer and project revenue?"
- "Can you set up WIP tracking for campaign and project work?"
- "How would you handle client media spend and pass-through costs?"
- "Are you a registered BAS agent?" Verify at tpb.gov.au.
An agency that gets clear, specific answers to all four has found a bookkeeper who understands agency economics, not just bookkeeping in general terms.
What This Typically Costs
Fixed monthly bookkeeping for a marketing agency generally runs from $450 to $1,200 or more, depending on team size, client volume, and whether WIP and retainer utilisation reporting are included. Quoted after a free assessment of your actual file, not a generic price list.
The Bottom Line
An agency that cannot see WIP, cannot separate retainer from project revenue, and cannot see which retainers have quietly outgrown their fee is running on a healthy-looking total that may be masking real losses underneath. Get all three visible monthly, and pricing and staffing decisions finally rest on evidence instead of how busy the team feels.