"Fractional CTO" is one of those titles that sounds clear until you try to explain it. Here's the plain version, without the consultant gloss.
A fractional CTO is a senior technical leader who owns your technology direction part-time — usually a day or two a week — instead of being a full-time hire. The "fractional" part is about time, not seniority. You get the same level of judgement you'd get from a full-time CTO; you just don't pay for five days when your stage of business only needs two.
What it isn't
It's easy to confuse the role with three things it isn't:
- It isn't a consultant. A consultant hands you a report and leaves. A fractional CTO stays accountable for what actually ships.
- It isn't a contractor. A contractor executes a defined spec. A fractional CTO decides what the spec should be.
- It isn't a part-time employee. You're not buying hours. You're buying ownership of an outcome.
What it actually involves
In practice the work clusters around a few things: setting the technology and AI strategy, making the architecture decisions that are expensive to get wrong, leading or hiring the engineering team, and — if the person is any good — staying hands-on enough to write code and review pull requests when it matters. The rare and valuable combination is someone who can sit in a board meeting in the morning and ship working software in the afternoon.
The best fractional CTOs are defined by ownership, not hours. They take the important problem nobody else owns, and make it theirs.
The signs you actually need one
You probably need a fractional CTO when: technical decisions are piling up and no one senior is making them; you're spending real money on developers without anyone setting their direction; you have a product idea but no one who can own the build end-to-end; or you've inherited something half-built and stuck. If any of those feel familiar, the gap is usually ownership, not effort.
If that sounds familiar, this breakdown of why startups fail at technical decisions explains the pattern in more detail.
What it costs
Day rates vary widely with experience and the value at stake. As a rough UK guide, expect senior fractional CTO work in the region of £700–£1,000 a day, often structured as a monthly retainer for ongoing leadership. The economics work because you're paying for a fraction of a senior person's time rather than a full salary, equity, and the cost of a bad hire.
The honest test
If you can write a tight spec and just need it built, you want a contractor. If you want advice and a roadmap, you want a consultant. If you have an important, half-defined technical problem and nobody to own it through to live — that's the moment for a fractional CTO.
If you're weighing options right now, read fractional CTO vs full-time vs consultant for a practical decision guide.
If that’s where you are, tell me about it. Get in touch, no pitch.