What Every Tech Startup Founder Gets Wrong About Gross Margin (and How CFOs Fix It)

Gross margin — revenue minus cost of goods sold, as a percentage of revenue — sounds like a simple number. For tech founders it’s routinely one of the least understood, because software and digital services don’t have an obvious, physical cost of goods sold the way a manufactured product does. That ambiguity is exactly where the mistakes creep in, and by the time they show up in a fundraise data room, they’re a lot more expensive to fix than they would have been a year earlier.

Where Founders Get It Wrong

Underestimating true COGS. Cloud hosting, infrastructure costs, and customer support are all genuine costs of delivering the product, but founders frequently exclude some or all of them from COGS — usually because they don’t feel like a “cost of goods” in the way a manufacturer’s raw materials do. The result is a gross margin that looks better than the business actually is.

Misclassifying expenses in the other direction. The reverse mistake also happens: R&D or marketing spend gets bundled into COGS, artificially depressing gross margin and distorting decisions that get made against it.

Ignoring variable, usage-based costs. Third-party API fees, payment processing charges, and usage-scaled infrastructure costs move with volume in ways that can catch a founder off guard — a cost structure that looked fine at low volume can compress margin significantly once usage scales.

Pricing without margin discipline. Pricing decisions are often made on competitive positioning or growth targets without a clear view of what they do to margin. Underpricing to win market share is a common and specific way growth-stage tech companies quietly erode their own economics.

Not tracking the trend. A single gross margin snapshot tells you very little. A margin that’s been quietly declining for several quarters — from rising infrastructure costs, competitive pricing pressure, or customer mix shift — is a genuinely useful early warning signal that gets missed when nobody’s watching the trend specifically.

Chasing revenue growth at the expense of margin. Aggressive discounting and rising customer acquisition costs in pursuit of top-line growth can leave a business growing revenue while its underlying economics quietly deteriorate — a pattern that reads very differently to an investor doing diligence than it does to a founder celebrating a growth number.

What a CFO Actually Does About This

The fix isn’t complicated in principle, but it requires someone with the time and discipline to do it consistently rather than once a year:

• Correct COGS classification — building a clear, consistent definition of what counts as cost of goods sold for the specific business, and applying it consistently rather than reclassifying costs opportunistically.
• A genuine unit economics model — understanding margin at the level of a customer, a transaction, or a product line, not just as a single blended company-wide figure that can hide real variation underneath it.
• Pricing tied to margin targets, not just competitive positioning — so a pricing decision is made with a clear view of what it does to the business’s economics, not made in isolation from them.
• Trend monitoring as standard practice, not a once-a-year exercise — catching margin compression while there’s still time to act on it rather than discovering it in fundraise diligence.

Why This Matters More at Fundraise

Investors scrutinise gross margin closely because it’s one of the clearest signals of unit economics and long-term operating leverage — a business with strong gross margin has genuine room to invest in growth once it scales; one with weak or declining margin doesn’t, regardless of how impressive the revenue line looks. A founder who can explain their margin clearly, with a defensible COGS definition and a credible trend, is in a materially stronger position in diligence than one who’s never had the number properly interrogated before an investor does it for them.

How FD Capital Can Help

FD Capital places fractional CFOs into tech startups who bring exactly this discipline — correcting COGS classification, building genuine unit economics, and keeping margin trend visible before it becomes a fundraise problem. If your gross margin has never really been stress-tested, we’re happy to talk through what a fractional CFO could do about it.

This article is provided for general information purposes and does not constitute professional advice. FD Capital Recruitment Ltd is registered at Companies House (no. 13329383) and is operated by an ICAEW-registered practice.

Adrian Lawrence

Adrian Lawrence FCA is the founder of FD Capital and a Fellow of the Institute of Chartered Accountants in England and Wales (ICAEW). He holds a BSc from Queen Mary College, University of London, and has over 25 years of experience as a Chartered Accountant and finance leader working with private, PE-backed and owner-managed businesses across the UK. He founded FD Capital to connect growing businesses with the Finance Directors and CFOs they need to scale — and personally interviews candidates for senior finance appointments.