How to Track Agency Profitability by Client, Retainer, and Project

Most agencies know what a client pays them. Fewer know what that client costs to service after delivery time, contractors, software, media spend, payment fees, meetings, reporting, and rework are counted.

That gap is where profit disappears. A client can be your largest account by revenue and still be your weakest account by margin.

The basic client-margin formula is simple: (Client Revenue - Direct Costs - Allocated Overhead) ÷ Client Revenue. The hard part is feeding that formula with clean data every month, without turning the agency into a finance department.

To track agency profitability by client, you need three layers: recognised revenue, delivery labour cost, and direct expenses. For retainers and fixed-fee work, you also need budget burn, because the margin changes every time the team absorbs another call, revision, or out-of-scope request.

This guide is a practical operating model. It covers the metrics, the workflow, and three tool levels: Toggl Track for lightweight time and profitability reporting, Harvest for time plus invoicing and payments, and Teamwork for fuller client-work profitability management.

What does client profitability actually mean?

Client profitability means the profit left after the revenue from a client is matched against the work and costs needed to deliver it. Revenue on its own is a sales number, not a profitability number.

Start with recognised client revenue, then subtract labour cost, contractor cost, software or media expenses, payment fees, and allocated overhead where you want a truer margin. If overhead is excluded, call it delivery margin rather than net profit.

Labour cost should use loaded cost rates where possible. That means salary or day rate plus employment costs and a sensible share of management overhead, rather than the team member’s billable rate.

The upside of this approach is that it shows which clients genuinely fund the agency. The downside is that loaded rates take work to maintain, especially when salaries, freelancers, and staffing mix change during the year.

A small agency can start with simpler cost bands: junior, midweight, senior, strategist, and contractor. It will be less precise than person-by-person rates, but it is better than treating every hour as free.

Which metrics should agencies track by client?

Track five numbers first: profit, margin, effective hourly rate, budget burn, and write-offs. These give you enough signal to make pricing and scope decisions without building a full finance system.

Client profit is recognised revenue minus labour cost and direct expenses. Client margin is profit divided by revenue, usually shown as a percentage.

Effective hourly rate is useful for retainers and fixed-fee projects. Divide the fee by the actual hours worked, then compare it with your target blended rate.

Budget burn shows how much of the agreed budget has been used. For fixed-fee work, compare actual hours or cost to the original estimate and the latest estimate to complete.

Realisation matters for time-and-materials work. Track billable time against invoiced time, then record any written-off time, discounting, or support work that never reaches the invoice.

These metrics are simple, but they rely on discipline. If account management, QA, reporting, and client calls are missing from timesheets, the margin will look healthier than it is.

How should you track retainers, fixed-fee projects, and T&M work?

Separate reporting by engagement type, because each model fails in a different way. Retainers are predictable, but they are vulnerable to over-servicing. Project work can carry stronger per-engagement margins, but it is exposed to scope creep and underquoting.

For retainers, track the monthly fee, hours burned, labour cost, contractor cost, direct expenses, meetings, reporting, revisions, and out-of-scope requests. The key metric is effective hourly rate by month.

A £5,000 monthly retainer looks healthy at 40 hours because the effective hourly rate is £125. At 80 hours, the same retainer falls to £62.50 before labour cost and expenses are counted.

For fixed-fee projects, track the fixed fee against actual cost, budget used, remaining estimate, and expected margin at completion. Waiting until the final invoice is too late, because the overrun has already happened.

For time-and-materials work, track billable hours, non-billable support time, write-offs, invoice status, and payment fees if the tool collects money for you. T&M can protect margin, but sloppy invoicing and unbilled time still leak profit.

The reporting cadence should match the risk. Review retainers monthly, fixed-fee projects at kickoff, midpoint, and wrap, and T&M work before every invoice run.

How do you build a simple client profitability mini-P&L?

A client profitability mini-P&L should have one line per client, retainer, or project. It does not need to be pretty; it needs to be complete enough to expose margin leaks.

Use columns for revenue, tracked hours, loaded labour cost, contractor cost, software or media expenses, payment fees, profit, margin, and scope notes. Add a column for target margin so the variance is visible.

For example, a client with £10,000 revenue, £4,500 labour cost, £1,000 contractors, £500 direct expenses, and £300 allocated overhead has £3,700 profit. The margin is 37%, assuming those are the only included costs.

The benefit of this format is that finance, account management, and delivery can discuss the same numbers. The limitation is that it depends on time entries and expense tagging being consistent.

Create standard client names, project names, retainer names, and task categories before the work starts. If one person logs “Client A SEO” and another logs “A Ltd organic”, reporting becomes a cleanup job.

For overhead, choose a method and stick with it. Some agencies allocate overhead by revenue share, some by labour hours, and some only use loaded cost rates. The wrong consistent method is usually more useful than a different method every month.

What time should you track for accurate agency profitability?

Track all time that exists because the client exists. Production time alone will understate the real cost of service.

Include client calls, async communication, revisions, QA, reporting, internal meetings, project management, account management, onboarding, and renewal work. These are easy to dismiss individually, but they compound across a retainer.

Create required time categories that map to how the agency runs: strategy, production, design, development, account management, project management, QA, reporting, and rework. Keep the list short enough that people use it.

Ask the team to enter time daily or at least weekly. The upside is cleaner data; the downside is that leaders must review compliance, or the process drifts after two weeks.

Add budget alerts where your tool supports them. A fixed-fee project that has burned 70% of its hours at 40% completion needs a scope or staffing decision, not a nicer dashboard.

Timesheet review should be operational, not punitive. Look for missing categories, untagged entries, unusual spikes, and work logged to the wrong client before the month closes.

Do you need Toggl Track, Harvest, or Teamwork?

Choose the tool based on where the profitability work needs to live. Some agencies only need better time data, while others need profitability tied to invoices, retainers, budgets, resources, and project delivery.

Toggl Track is the cleanest fit if the main problem is time capture and client or project profitability reporting. AgencySoftware records it as Best Time Tracking, with pricing at Free, then $9.

Toggl Track Premium includes profitability analysis and fixed-fee projects. Its profitability reports use revenue, cost, profit, and margin, with a default breakdown by client and project.

For hourly projects, Toggl Track calculates revenue from billable hours multiplied by billable rate. It calculates cost from tracked hours multiplied by cost rate, then shows profit and margin.

That makes Toggl Track useful if the agency already has project management elsewhere. The trade-off is that profitability analysis sits on Premium, and paid-plan fees include vacant licences until an admin removes them.

Harvest is the better fit if time tracking needs to connect directly to invoicing, retainers, and online payments. AgencySoftware records it as Best Time + Invoicing, with pricing at Free, then $11.

Harvest supports Time & Materials, Fixed Fee, and Non-Billable projects. Retainers can draw from Time & Materials or Fixed Fee projects, which suits agencies that invoice from tracked work.

The limitation is plan gating and project structure. Harvest lists profitability reporting on Enterprise, and a project can be Fixed Fee or Time & Materials, rather than both at once.

Harvest also has payment-fee details to check before using it for collections. It supports Stripe and PayPal Standard, and Harvest says some accounts pay an additional Harvest fee on card and ACH payments.

Teamwork is the fit if profitability needs to sit inside client work, budgets, retainers, invoices, and resource planning. AgencySoftware records Teamwork as Best for Client Work, with pricing at Free, then $10.99.

Teamwork’s Free plan is limited to 5 projects and 5 users, which is useful for testing but tight for a growing agency. Its 14-day trial gives a cleaner way to test paid workflows before committing.

Teamwork Accelerate includes time budgets, retainers, invoices from logged time, and HubSpot and QuickBooks connections. Optimize adds financial budgets and revenue, cost, and profitability insights.

The strength is that delivery and profitability can live in one operating system. The downside is that the deeper financial features are plan-gated, so a simple time-tracking problem may not justify the extra system change.

TeamworkAI can project revenue, costs, and profits from historical profitability data. Treat that as forecasting support rather than truth, and remember that usage-based AI credits are scheduled to launch in September 2026.

How should the monthly profitability workflow run?

Run profitability as a monthly operating rhythm, not as a post-mortem after a client renewal goes badly. The goal is to see the leak early enough to change the work, price, or staffing.

Step 1: standardise clients, projects, retainers, and task categories across your tools. This is dull setup work, but it prevents reporting from splitting the same client across several labels.

Step 2: set billable rates and internal cost rates before the work starts. If rates are added later, the first month’s margin becomes a reconstruction exercise.

Step 3: require time entries daily or weekly, tagged to the correct client and project. Weekly is easier to enforce, but daily is more accurate for short meetings and quick client requests.

Step 4: add contractor costs, software, media, payment fees, and other direct expenses to the same client or project record. If these stay in a separate finance file, delivery leaders will miss them.

Step 5: review margin monthly for retainers. For fixed-fee projects, review at kickoff, midpoint, and wrap, with a forecast of expected margin at completion.

Step 6: act on what the numbers show. Reduce scope, add a change-order process, raise the retainer, move work to T&M, change staffing mix, or stop absorbing requests that should be billed.

What should you do when a client is unprofitable?

Do not start by firing the client. Start by finding the leak, because some unprofitable accounts can be fixed with clearer scope, cleaner staffing, or better billing discipline.

If meetings are the issue, cap them in the retainer and move extra sessions to paid consulting. If revisions are the issue, define rounds and charge for additional changes.

If senior people are doing work that could be handled by juniors, adjust the staffing mix. The upside is margin recovery, but the risk is quality drift if handover and review are weak.

If the fee is simply too low, use the next renewal to reprice the work against actual hours and expenses. Show the client the new scope and service level, rather than presenting a vague price rise.

If the client keeps pushing beyond scope, introduce change orders or move the engagement to time and materials. That protects the agency, but it can create friction with clients who expect unlimited access.

The point of tracking agency profitability by client is not to produce a spreadsheet for its own sake. It is to make commercial decisions before the agency has already donated a quarter of its margin.

Which tool should you choose for agency profitability tracking?

Choose Toggl Track if you already have a project-management setup and need reliable time data plus client and project profitability reporting. It is the lightest option here, but profitability analysis is not on every plan.

Choose Harvest if invoicing from tracked time is central to the workflow. It is stronger than a plain timer for billing operations, but profitability reporting and payment costs need careful checking.

Choose Teamwork if the agency needs client-work delivery, retainers, budgets, invoices, resource planning, and profitability insights in one place. It is the most operational option, but deeper financial features sit behind higher plans.

If the agency is still choosing its wider stack, solve the workflow before buying software. Profitability tracking fails less often because of the tool, and more often because time, expenses, and scope changes are not recorded consistently.