The Five Numbers a Scaling Founder Should Recite From Memory
The short answer: the five financial KPIs a scaling founder should know from memory are gross margin (by line, not just blended), cash runway, debtor days, revenue per head and pipeline coverage. Together they tell you, on any given Tuesday, whether the business is actually well.
The short version
| KPI | What it tells you | The warning sign |
|---|---|---|
| Gross margin, by line | Which products or services actually make money | Trusting the blended average past about £5M |
| Cash runway | How many months you could make payroll if income stopped | Not being able to answer in one breath |
| Debtor days | How long your cash sits in customers’ accounts | Drifting from 30 days towards 60 |
| Revenue per head | Whether growth is productive or just busy | Flat or falling as you hire |
| Pipeline coverage | Committed revenue against the number you need | Unweighted, unreviewed, mostly hope |
There’s a small test I find myself applying in early conversations with a founder. I ask them a few numbers about their own business. Nothing exotic. And I watch whether the answer comes back straight away, or whether they reach for a laptop.
It’s not a gotcha. Plenty of brilliant founders don’t hold these figures in their heads, and the business has done fine so far without it. But there’s a shift that happens somewhere on the way to £10M, where not knowing them stops being forgivable and starts being dangerous. The numbers get bigger, the decisions get faster, and “let me check and come back to you” becomes a genuine handicap.
So here are the five I think a scaling founder should be able to recite from memory — and, just as importantly, what “good” looks like for each as you move from £1M through £5M to £10M. Because the number itself matters less than whether you know it, and whether it’s moving the right way.
1. Gross margin — and not the rough version
At £1M, “about 60%, I think” is survivable. By £10M it’s a liability. The businesses that scale profitably know their gross margin to the point, not the estimate, and they know it by line. One product looks healthy on the blended average and is losing money underneath, and the average hides it. The founders who get to £10M in good shape are the ones who stopped trusting the blended number somewhere around £5M and started looking underneath it, every single month. (Where margin quietly leaks.)
2. Cash runway — how long you’d last on what you have
You can argue about profit. You can’t argue with an empty bank account. Runway is the number that decides whether you sleep. Early on, a gut feel for “we’re fine for a few months” gets you by. As you scale, that has to become a proper thirteen-week view, and then a rolling forecast that updates as reality does. The number to hold in your head is a blunt one: if the money stopped coming in tomorrow, how many months could you still make payroll? If you can’t answer that in one breath, it’s the first one to fix. (Why profit and cash drift apart.)
3. Debtor days — how long your cash sits in someone else’s account
This is the one founders most often ignore, and it’s pure self-harm. Every day a customer takes to pay you is a day you’re funding their business instead of your own. At £1M it’s an irritation. At £10M, a debtor book drifting from 30 days out to 60 can swallow an alarming amount of cash — money you’ve already earned, sitting in someone else’s account. And the fix isn’t just watching the number. It’s chasing it down, on purpose, as a discipline. The businesses that manage their debtor days are buying themselves runway for free, and most of their competitors never think to. (You also have legal rights on late business payments.)
4. Revenue per head — whether growth is earning its keep
This one catches people out. Revenue goes up, everyone feels successful, and nobody notices that headcount went up faster. Revenue per head is the cleanest single check on whether your growth is actually productive or just busy. It doesn’t need to hit a specific figure — the right number varies enormously by sector — but the trend is the tell. If revenue per head is flat or falling as you scale, you’re adding people faster than you’re adding value, and that catches up with you eventually. If it’s rising, the growth is real. (What each new hire really costs.)
5. Pipeline coverage — committed revenue against the number you need
The last one looks forward. It’s the ratio between what you’ve got contracted or in credible pipeline, and the number you actually need to hit. Early on this lives mostly on hope and a founder’s optimism. By £10M it needs to be weighted, honest, and looked at weekly, because the gap between “we’ll be fine” and “we’re going to miss” is usually visible months ahead — if anyone’s watching the right number. The cash crises I see rarely come out of nowhere. Almost always, the warning was sitting in a pipeline nobody was tracking properly.
The card
I’ve put all five into a single card — it’s the image at the top of this page — with a rough sense of what each looks like at £1M, £5M and £10M. It’s directional, not gospel; your sector will shift the specifics. But it’s designed to be screenshotted and stuck somewhere you’ll see it. If you can glance at it and answer every row about your own business without reaching for a laptop, you’re in good shape. If two or three make you pause, you’ve just found your priorities for the next quarter.
Here’s the action, and it’s a small one. Take the card. Go through the five, out loud, about your own business. Mark the ones where the honest answer is “I’d have to check.” That short list — the numbers you can’t yet recite — is the most useful thing you’ll produce this week.
And if it turns out the numbers exist somewhere in your systems but never quite reach you in a form you can actually use, closing that gap is exactly the sort of work our CFOs do. WrightCFO is a practice of fractional CFOs — senior finance people who come in alongside you and turn the data you already have into numbers you can run the business on. If that’s of interest, book a 30-minute call with me.
— Sophie
Frequently asked questions
What financial KPIs should a founder track?
Five cover most of what matters in a scaling business: gross margin by product or service line, cash runway, debtor days, revenue per head and pipeline coverage. Each should be known, tracked monthly or weekly, and watched for trend as well as level.
How do you calculate cash runway?
Divide the cash you have available by your average monthly net cash outflow, or for a stress test, by your monthly fixed costs assuming no new income. The result is the number of months the business could keep paying its bills.
What are good debtor days for a UK business?
It depends on your agreed terms and sector, but debtor days should stay close to your payment terms. A drift from around 30 towards 60 days ties up a large amount of cash in a growing business.
What is revenue per head?
Total revenue divided by the number of full-time-equivalent staff. The right level varies by sector; the trend matters most, because falling revenue per head means headcount is growing faster than the business.
What is pipeline coverage?
The ratio of contracted and credibly weighted pipeline revenue to the revenue target for a period. Tracked weekly, it gives early warning of a shortfall months before it shows up in cash.
This article was first published in The Scaling CFO, Sophie Wright’s fortnightly newsletter for founders between £1M and £20M. Subscribe free. Related reading: Babylon Health and client profitability.
Sophie Wright is the founder of WrightCFO, a UK fractional CFO practice. WrightCFO provides fractional (part-time) Chief Financial Officers to founder-led and private equity-backed businesses, typically between £1M and £20M in revenue, scaling towards and beyond £10M. The practice specialises in cashflow forecasting, margin and pricing, investor-ready reporting, post-acquisition integration and exit readiness, across the technology, creative, media, professional services and not-for-profit sectors. WrightCFO works alongside clients’ existing accountants rather than replacing them.
