What is a fractional CTO?

A fractional CTO is a chief technology officer who holds the seat at a company for one to three days a week, on an ongoing basis, owning architecture, technical hiring, security and delivery feasibility, without being the person writing most of the code. In the UK the day rate is £800 to £1,400 in 2026, and two days a week is the most common shape.

Also called

Part-time CTO, Virtual CTO, Portfolio CTO and Technical advisor, once the days drop below one a week. The job is the same under each name; the words differ by market and by who is selling it. What a fractional executive is covers the pattern across every seat.

What the title means in practice

Architecture, and the choices you live with for yearsThe stack, the data model, build or buy, and when to rewrite. These are the decisions a non-technical founder cannot evaluate and an agency has no incentive to question, and they are the core of the seat.

Hiring engineers is often the real jobWriting the spec, running the technical interview, setting the level and the salary, and saying honestly when an agency is the better answer for now. A fractional CTO who has built teams before is worth the day rate for this alone.

Managing the agency or the outsourced teamMany companies arrive with an agency building the product and nobody senior checking the work. The fractional CTO reviews the architecture, the code quality and the estimates, and holds the agency to them.

Due diligence, in both directionsBefore a raise, investors ask who owns the technology and what the risks are. The fractional CTO answers, prepares the technical data room, and has usually sat on the other side of that table.

What a fractional CTO is not

Not a development agency. Builds what it is asked to build, with no incentive to say the request is wrong. Fractional CTO or a development agency.
Not a technical co-founder. Equity, full time and permanent, which is a different bet from a seat held two days a week. Fractional CTO or a technical co-founder.
Not a head of data. Owns the data model and the analytics; the fractional CTO owns the platform they run on. Fractional CTO or a head of data.

Fractional CTO job description

The scope a brief for this seat usually lists. Each item is a thing the person owns, not a task they perform; at one to three days a week the owning is the job.

Architecture and technology choices, documented and defended
Roadmap feasibility: what can ship by when, at what cost and risk
Engineering hiring: specs, interviews, levels, and the first engineering manager
Security, reliability and the risk register nobody else keeps
Oversight of agency or outsourced development, including code review and estimates
Technical due diligence preparation before a raise or a sale

Reports to the chief executive, works with the product lead, and manages the engineers or the agency building the product.

What it costs

A fractional CTO charges £800 to £1,400 a day in the UK in 2026. Higher end for regulated sectors, AI systems and technical due diligence. At two days a week that is £6,133 to £10,733 a month, before VAT and with no employer costs on top, because the executive is not an employee. The full arithmetic, at every day count and against a full-time hire, is on the fractional CTO cost page.

Where the word comes from

Technology went fractional as non-technical founders outsourced the build and discovered that nobody senior was checking it. Deep tech clusters and AI products have pushed the demand further, because the architecture decisions arrive before the company can afford a full-time CTO.

Common questions

What does fractional CTO mean?

A chief technology officer who holds the seat for a fraction of the week, usually one to three days, on an ongoing basis. They own architecture, technical hiring, security and what the roadmap will really take to build, and manage whoever is writing the code.

Does a fractional CTO write code?

Some, early on, and rarely most of it. The seat is judgement, hiring and oversight. A company that needs somebody to write most of the code needs a senior engineer or an agency, and a good fractional CTO will say so and help hire them.

When should a startup hire a fractional CTO?

When a non-technical founder is relying on an agency they cannot evaluate, when every change takes longer than the last one, when two engineers are making architecture decisions with nobody above them, or when a raise is coming and investors will ask who owns the technology.

How much does a fractional CTO cost?

£800 to £1,400 a day in the UK in 2026, most often at one to two days a week. The higher end is for regulated sectors, AI systems and technical due diligence. The monthly and annual arithmetic is on the cost page for the seat.

From the word to the person

Verified fractional CTOs, rate on the profile

What the seat covers and who is on the bench, how to interview for it, or brief Operator Search and the shortlist comes to you.