Is a fractional CTO cheaper than a full-time CTO?

In almost all cases, yes. A fractional CTO at two days per week typically costs £144,000–£240,000 per year with little or no equity, versus £230,000–£410,000+ plus 1–3% equity for a full-time hire. The day rate is higher, but the total cost is far lower because you only pay for part of the week.

Can a fractional CTO become a full-time CTO later?

Sometimes, but the more common and valuable path is for the fractional CTO to define the full-time role, raise the hiring bar, run the search, and onboard a permanent successor. They act as a bridge to the full-time hire rather than necessarily becoming it.

How many days a week does a fractional CTO work?

Most fractional CTO engagements run between one and three days per week. Below one day it is hard to maintain enough context to be effective; above three you are approaching the cost of a full-time hire without the full-time commitment.

When should I switch from a fractional to a full-time CTO?

When technology becomes core to your competitive advantage, your engineering organisation is large enough that leadership is a full-time job on its own (often around 25+ engineers), or the role starts to demand constant, real-time decision-making rather than periodic strategic input.

Fractional CTO vs Full-Time CTO: How to Decide

At some point, most scaling companies face the same question: do we hire a full-time CTO, or bring in a fractional one? Both give you senior technical leadership. The difference is in availability, cost, commitment, and what stage of the company they fit best. Choosing wrong is expensive in either direction — a premature full-time hire burns equity and runway, while leaning on fractional leadership too long can leave you without the daily presence a maturing organisation needs.

This guide lays out the real trade-offs so you can decide based on your situation rather than a default.

At a Glance

Dimension	Fractional CTO	Full-Time CTO
Time commitment	1–3 days per week	Full-time
Typical annual cost	£144,000–£240,000	£230,000–£410,000+
Equity	Little or none	Typically 1–3%
Time to start	Days	3–6 month search
Availability	Key decisions and meetings	Every day, every decision
Best for	Direction, structure, specific problems	Tech-as-core, large org, constant presence

The rest of this guide unpacks what's behind each row.

The Core Difference

A full-time CTO is a permanent executive: fully dedicated, deeply embedded, and incentivised through salary and significant equity. A fractional CTO delivers the same calibre of leadership on a part-time basis — typically 1–3 days per week — for a monthly retainer and little or no equity. If you want the full picture of the role itself, start with what does a fractional CTO do.

The distinction isn't seniority. A good fractional CTO has usually held full-time CTO or VP roles before. The distinction is *dosage and commitment*: how much of their time you get, and how permanently they're tied to your company.

Cost: The Most Visible Difference

The financial gap is stark. A full-time CTO at a scaling startup typically costs £230,000–£410,000+ per year in salary, benefits, and overhead — plus 1–3% equity that can be worth millions on a good outcome, plus a months-long, often six-figure search to find them.

A fractional CTO at two days per week typically runs £144,000–£240,000 per year, usually with no meaningful equity and a start measured in days. We break the numbers down fully in how much does a fractional CTO cost. The headline: fractional is often 40–60% cheaper in cash and preserves the equity you'd otherwise give away.

But cost alone shouldn't decide it. The question is what each model buys you.

Availability and Depth of Involvement

This is where the trade-off is real. A full-time CTO is in every meeting, available for every urgent decision, building deep relationships across the whole company, and able to drive culture day to day. A fractional CTO is present for the decisions and meetings that matter most, with asynchronous availability in between — but they are not there every hour, and they're holding context across more than one company.

For a company whose primary need is direction, structure, and a handful of high-stakes decisions, fractional coverage is plenty. For a company where technology *is* the product and leadership presence is needed constantly — say, a deep-tech startup making novel architectural bets every week — full-time presence earns its cost.

When a Fractional CTO Is the Right Choice

You're pre-Series A or early Series A and need senior leadership without burning equity or runway
Your need is strategic — roadmap, architecture, team design, hiring — rather than constant daily presence
You want to fix a specific problem: stalled delivery, a migration, an upcoming raise
You're a non-technical founder who needs a translator and guide more than a full-time operator — see our non-technical founder's guide
You're not yet sure what kind of full-time CTO you'll eventually need, and want senior input to figure that out

When a Full-Time CTO Is the Right Choice

Technology is the core of your product and competitive advantage
Your engineering organisation is large enough (often 25+ engineers) that leadership is a full-time job on its own
You need a permanent face for the team, recruiting, and the board over a multi-year horizon
You've raised enough that the cost and equity are justified by the stage
The role requires constant, real-time decision-making rather than periodic strategic input

The Bridge Most Companies Miss

These aren't mutually exclusive, and treating the decision as binary is the most common mistake. The most effective path for many scaling companies is to start fractional and convert to full-time when the stage demands it.

A fractional CTO can run for the months before you're ready to commit, then help you define the full-time role precisely, raise the hiring bar, run the search, and onboard their successor. You get senior leadership immediately, you avoid a premature six-figure hire, and you reach the full-time decision knowing exactly what you need rather than guessing. For more on getting that timing right, see when should a startup hire its first CTO.

How to Decide

Ask three questions. First: is your core need strategic or operational-and-constant? Strategic favours fractional; constant operational presence favours full-time. Second: what's the cost of getting the decision wrong right now? If you can't yet define the full-time role well, a premature hire is the bigger risk. Third: what does your runway support? Equity and cash you spend on leadership is leadership you can't spend on building.

If you're still weighing it up, book a strategy call — we'll give you an honest read on which model fits your stage, even when the honest answer is "not us yet."