Fractional CTO vs Full-Time CTO: Which Does Your Startup Need?
Fractional CTO vs Full-Time CTO: Which Does Your Startup Need?
If you're building a tech startup without technical founders, the question of whether to hire a fractional CTO vs full-time CTO: is one you'll face early. And honestly? It's not a simple either/or.
We've spent 25+ years helping startups get this decision right. We've seen founders burn through £300k+ on full-time CTOs who weren't the right fit. We've seen others struggle with part-time fractional arrangements that left them hanging during critical moments. So let's talk about what actually works, and more importantly, when neither option is what you really need.
The Real Difference Between Fractional and Full-Time
A full-time CTO: is your in-house technology leader: present every day, embedded in your culture, focused exclusively on your problems. They're building your roadmap, leading your technical strategy, hiring engineers, and living and breathing your product.
A fractional CTO: is typically an experienced technologist who works with you 1–3 days per week (or however much time your agreement specifies). They bring strategic guidance, technical decision-making, and credibility without the full commitment—or full cost.
That sounds simple. The reality is messier.
Full-Time CTO: When It Makes Sense
You probably need a full-time CTO if:
- You're already spending £2–4m+ annually on development.: At that scale, a full-time CTO (£120–200k all-in) is a rounding error and will pay for themselves in efficiency gains alone.
- You're in a highly regulated space: (fintech, health tech, insurance). You need someone in the room when compliance decisions are made.
- Your product is technically complex: and requires constant architectural decisions. You can't afford to wait for someone to come in on Thursdays.
- You need to hire and retain a strong engineering team.: Engineers want to work with brilliant technical leaders. A fractional CTO rarely has the presence for that.
- You've already raised Series A: and need to operate at a different tempo.
The thing about full-time CTOs is they're not cheap. You're looking at £120–180k salary, benefits, pension contributions, employer's NI. By the time you factor everything in, it's closer to £160–230k annually. Add equity (they'll ask for 1–5%), and you're making a serious commitment.
And sometimes, that commitment goes wrong.
We've seen founders hire experienced CTOs who were brilliant at scale but bored with early-stage chaos. We've seen others hire talented engineers who couldn't make strategic decisions. We've seen personalities clash in ways that hurt the entire team. A full-time hire is a marriage. You need to get it right.
Fractional CTO: The Lean Approach
A fractional CTO typically costs £150–250/hour or £4–8k per month for 1–2 days weekly. That's a fraction of a full-time salary. They come in, review your technical decisions, help you avoid expensive mistakes, and leave. No office politics. No cultural friction. Just expertise.
It works brilliantly if:
- You're pre-seed or early-seed: , still figuring out your product. You need strategic input, not 40 hours of full-time execution.
- Your technology stack is relatively straightforward.: You need someone to check your work, not architect systems from scratch.
- You already have solid engineering leadership: , but you're missing executive-level technical credibility for investors or partnerships.
- You have specific, time-bound problems.: Maybe you need help evaluating your cloud infrastructure, or deciding between building in-house vs outsourcing. A fractional CTO can tackle that in a month.
- You can't afford full-time: , but you need more than just hiring a CTO coach for a few hours here and there.
The trade-off? Fractional CTOs aren't always available when you need them. They're splitting their attention across multiple clients. When something breaks at 2 a.m. and you need technical leadership, they're not there. They know less about your codebase and team than someone living it daily.
The Comparison
| | Full-Time CTO: | Fractional CTO: | Technical Co-Founder: |
|---|---|---|---|
| Monthly Cost: | £10–20k | £4–8k | 0 (equity only) |
| Time Commitment: | 40+ hrs/week | 8–40 hrs/week | Variable, but usually 50+ hrs/week |
| Hiring Leadership: | Yes | Rarely | Often |
| Available for emergencies: | Yes | Sometimes | Yes |
| Investment credibility: | High | Medium | Very High |
| Best for early-stage: | No (overqualified cost) | Yes | Yes |
| Best for scaling: | Yes | No | Yes |
| Requires cultural fit: | Yes (high risk) | No | Yes (critical) |
What Everyone Gets Wrong
Here's the thing that nobody tells you: sometimes the real problem isn't whether you need full-time or fractional.
You might actually need a technical co-founder.:
A technical co-founder is someone who believes in your mission enough to invest their own equity and time. They're not brought in to "lead" the tech team—they're building the thing with you. They care differently. They make decisions faster. They don't need to understand your business model because they're betting their future on it.
Over 25 years, we've seen far more successful startups built with a technical founder than without one. When founders have tried to replace that with a hired CTO—full-time or fractional—they often hit a wall. The CTO is good, but they're not *invested*.
That's actually why we started working with founding teams the way we do. After 15 years doing agency work, we stepped back and thought: we should be equity co-founders, not contractors. Our first exit was worth £2m. Our best was worth £8m+. We weren't building systems for clients anymore—we were building for ourselves.
If you can find a technical co-founder, seriously consider it.
The Middle Ground: Hybrid Models
Some startups use what we call a "hybrid" approach: bring in a fractional technical leader early on (3–6 months), clarify your technology direction, and then either hire full-time or promote from within. This costs you £20–40k but saves you from making expensive mistakes.
Others do the opposite: start with a full-time hire but build an explicit exit plan. If it's not working by month 6, you part ways. It's brutal, but cheaper than staying in a bad marriage for 18 months.
Practical Questions to Ask Yourself
Do I have engineering leadership already?: If yes, you probably don't need a CTO at all—fractional or full-time. You need a CTO coach or advisor. If no, ask yourself whether you need someone full-time or part-time to build that.
How much am I spending on development?: Under £1m annually, fractional. Over £4m, definitely full-time. In between? It depends on complexity.
Can I live with this person making decisions I'm not sure about?: A CTO has to make calls. If you need approval on everything, hire a technical coach, not a CTO.
Am I hiring this person or partnering with them?: That's the real question. Hired CTOs are employees. They have job security, limited upside, and sometimes limited commitment. Partners are different. They move faster, take bigger risks, and care more.
What We'd Do (If You Asked)
If an early-stage founder came to us and said, "We need technical leadership," here's how we'd think about it:
- Do you have a technical co-founder?: If not, that's step one. Everything else is a patch.
- If you're going to hire:: Start fractional (£5–8k/month) for 3 months. See if you can find someone who might become a partner later.
- After 3 months, decide:: Does this person get equity and responsibility? Then make them a fractional partner (50–70% of full-time salary + 1–5% equity). Or do you need someone full-time? Or do you realise you need a co-founder?
- Don't stay fractional forever.: It's a transition tool, not a permanent solution. Either you commit or you don't.
The Bottom Line
There's no magic answer to "full-time or fractional?" It depends on your stage, your budget, your technical complexity, and honestly, whether you can find the right person.
But here's what we know from experience: the startup's that move fastest are the ones with technical founders. The ones that scale best are the ones with full-time technical leadership who can hire and build teams. And the ones that struggle most are the ones who thought a part-time hire could replace a genuine co-founder investment.
Start with the right foundation. Everything else follows.
Read Next
- What Is a Fractional CTO? (And Do You Actually Need One?)
- How Much Does a Fractional CTO Actually Cost?
Cooply is a technical founding team based in South Wales and Yorkshire. We partner with startups as equity co-founders, fractional CTOs, or on a hybrid basis—taking on 3–4 new ventures each year. If you're thinking about technical leadership for your startup, get in touch.: