Why Revenue Is a Terrible KPI on Its Own

You know how much you billed last month. That's the number most agency founders lead with. "We did £120k in March." It sounds good. It feels good. And it tells you almost nothing about whether your agency is actually healthy.

Revenue is a vanity metric. It doesn't tell you if you're profitable. It doesn't tell you if you're burning out your team. It doesn't tell you if you're pricing properly. And it certainly doesn't tell you if you're heading for a cash flow crisis in three months.

What you actually need is a set of financial KPIs that give you the full picture. The kind of numbers that go into proper management accounts. The kind that let you spot problems before they become emergencies.

Here are the eight agency KPIs finance-focused founders track monthly. If you're not looking at these, you're flying blind.

1. Gross Margin

Gross margin is the single most important number in your agency. It tells you how much money you keep after paying for the direct costs of delivering your work.

For most agencies, direct costs are salaries of delivery staff, freelancers, and the software tools your team uses daily. Everything else, rent, marketing, your own salary, accounting fees, is overhead.

The formula: (Revenue minus direct costs) divided by Revenue, expressed as a percentage.

If your agency bills £100k in a month and your delivery team costs are £45k, your gross margin is 55%. That's solid. A healthy agency typically runs between 50% and 65%. Below 45% and you're probably under-pricing or over-staffing. Above 70% and you might be under-investing in delivery capacity, which creates burnout.

Track this by client and by project. If one client consistently drags your margin down, you either need to raise their rate or fire them.

2. Net Profit Margin

Gross margin tells you about your delivery efficiency. Net profit margin tells you about your overall business model. This is what's left after every single cost: salaries, rent, software, marketing, accountancy, your own drawings, everything.

The formula: Net profit divided by Revenue, expressed as a percentage.

For a well-run agency, net profit margin should be between 15% and 25%. If you're below 10%, your overhead structure is too heavy. If you're above 30%, you might be under-paying yourself or not reinvesting enough, which is fine short-term but unsustainable.

Your net profit margin is the number that matters when you eventually sell. A buyer looks at your bottom line, not your top line.

3. Revenue Per Head

This is the classic agency efficiency metric. Total revenue divided by total headcount. It tells you how much revenue each person in your business generates.

The benchmark: A healthy UK agency typically runs between £80k and £150k revenue per head. A 10-person agency turning over £1.2m is at £120k per head. That's good.

If you're below £70k per head, you have too many people for the work you're selling. If you're above £160k, you might be under-staffed and running your team ragged, check your utilisation rate before celebrating.

Revenue per head varies by agency type. A recruitment agency can push higher because they have fewer direct delivery costs. A web design agency with heavy technical delivery will sit lower. The key is tracking your own trend month on month.

4. Utilisation Rate

Utilisation rate is the percentage of your team's paid hours that are actually billed to clients. If someone works 40 hours in a week and bills 32 of those to clients, their utilisation is 80%.

The benchmark: 75% to 85% is the sweet spot for most agencies. Below 70% and you're carrying too much bench. Above 90% and you have zero capacity for business development, internal projects, or handling unexpected client demands, which means scope creep will kill your margins.

Track this by role. A senior strategist might sit at 60% because they spend time on new business. A designer should be at 80% or higher. If your whole team is below 70%, you have a sales problem. If they're all above 90%, you have a pricing problem, you're not charging enough for the work.

5. Average Billable Rate

This is straightforward but often ignored. Total billable revenue divided by total billable hours. What are you actually charging per hour, on average, across all clients?

If you think you charge £100 per hour but your average billable rate comes out at £78, you have a problem. It means you're discounting, giving away free work, or not tracking time properly. All of those are margin killers.

Calculate this for each client. If Client A gives you an average rate of £95 and Client B gives you £60, you know exactly which one to push for a rate increase or replace.

6. Cash Runway

Cash is oxygen. You can be profitable on paper and dead in the water because your clients pay on 60-day terms while your staff expect salary every month.

Cash runway is the number of months you could continue operating if your revenue went to zero tomorrow. Divide your current cash balance by your monthly operating costs.

The rule of thumb: Three months is the minimum for a stable agency. Six months is comfortable. Anything below one month is an emergency.

If you're below three months, your priority is not growth. Your priority is extending your runway, negotiate better payment terms, chase overdue invoices, cut non-essential spend, or draw a factoring facility.

Your management accounts should show your cash position every single month. If they don't, you're guessing.

7. Debtor Days (DSO)

Days Sales Outstanding measures how long it takes your clients to pay you. The lower the number, the better.

The formula: (Total outstanding invoices divided by total annual revenue) multiplied by 365.

If you have £80k outstanding and your annual revenue is £960k, your DSO is 30 days. That's good. If your DSO is 60 days or more, you are effectively acting as a bank for your clients, and they're not paying you interest.

For agency founders, DSO is one of the most actionable KPIs. You can improve it immediately by tightening payment terms, charging interest on late payments, or moving retainer clients to direct debit. If your DSO is creeping up month on month, you have a collections problem that needs addressing now, not at year-end.

8. Project Profitability (Per Client)

This is the KPI that most agency founders don't track but should. Not just gross margin overall, but gross margin per project per client.

Some clients look profitable on the surface because they pay a high retainer. But if they consume disproportionate account management time, demand endless revisions, and cause scope creep on every project, they might actually be your least profitable client.

Run a profitability report for each client every quarter. Include all time spent, not just the time you billed. If you spent 10 hours on a project but only billed for 8, those 2 hours came out of your margin.

When you see the real numbers, you will almost certainly fire at least one client. Every agency founder I've shown this to has. And every one of them has been better off for it.

How to Get These Numbers Without Drowning

You do not need to build a spreadsheet from scratch. If you use Xero or QuickBooks, most of these KPIs can be generated from your management accounts. The key is setting them up properly from the start.

At Agency Founder Finance, we build management accounts for agency founders that show all eight of these KPIs every month. Our ICAEW qualified team structures your chart of accounts around agency-specific categories, delivery salaries, freelancer costs, retainer revenue, project revenue, so the numbers actually mean something.

If you're doing your own bookkeeping, here is the minimum setup:

  • Use separate nominal codes for delivery staff and overhead staff
  • Track time against projects in Xero or FreeAgent
  • Reconcile your invoices to time entries monthly
  • Run a project profitability report at least quarterly
  • Review your cash position weekly, not monthly

If this sounds like more than you want to handle, that is exactly what we're here for. We work exclusively with agency founders. We know the numbers that matter because we see them every day across dozens of agencies.

What to Do With These Numbers

Tracking KPIs is useless if you don't act on them. Here is a simple process:

Every month, review your management accounts. Compare each KPI to the previous month and the same month last year. If any KPI has moved more than 10% in the wrong direction, you have a problem to solve that week.

If gross margin drops, check if a specific project or client caused it. If utilisation drops, look at your sales pipeline. If debtor days increase, call your slowest-paying client tomorrow morning.

The point is not to have perfect numbers. The point is to see the trend before it becomes a crisis. A 2% drop in gross margin over three months is a warning. A 10% drop in one month is an emergency.

If you want to dig deeper into how to structure your agency finances, read our guide on agency finance essentials. If you want someone to build your management accounts for you, get in touch.