What Is a Fractional CTO? Role, Cost & When You Need One

What is a fractional CTO? It is a senior technology leader who works for your company part-time. They own the decisions a full-time chief technology officer would: architecture, technical hiring, supplier and budget oversight, and how the technology serves the business plan. You pay a monthly fee instead of a salary. With us that starts from £3,000 a month for an advisory arrangement and from £8,000 a month for a hands-on one. Employing a CTO costs about £115,571 a year at the £100,000 median advertised UK salary (ITJobsWatch, 6 months to 17 Oct 2026; the workings are below).

This article explains what a fractional CTO does, how the role differs from an interim CTO, a full-time hire and a technical co-founder, and the signs that you need one. It prices each route and covers when you do not need one, because many businesses that ask for a CTO need developers, a one-off review or a better brief. We build software as well as advise on it, so we say where that creates a conflict and what to ask any provider, including us.

Key takeaways

• A fractional CTO is a senior technology leader engaged part-time for ongoing decisions on architecture, hiring, suppliers and risk. Only the hours are fractional.
• You need one when technical decisions are stalling or are being made by people who cannot judge them. If the product just needs more building, you need engineers.
• Illustratively, employing a CTO at the median advertised salary of £100,000 costs about £115,571 a year in salary, employer National Insurance and minimum pension, before recruitment, bonus and equity.
• Our fractional CTO service starts from £3,000 a month (Advisory CTO) and from £8,000 a month (Hands-on CTO). Ask any provider how many days a month the price buys.
• Hire full-time when technology is the product and the work fills most of every week for years.

What is a fractional CTO?

A fractional CTO is a chief technology officer you share. They give your company a fraction of their working week or month, and their other commitments take the rest. Only the hours are fractional. The seniority is the same as a full-time hire’s.

The idea goes by several names. “Part-time CTO”, “virtual CTO”, “outsourced CTO” and “CTO as a service” all describe versions of it, and providers use the labels loosely. Read the proposal for what you actually get each month, because the label will not tell you.

The CTO is the person accountable for technology decisions: what gets built, with what, by whom, and at what cost and risk. In a small company the founder or the lead developer often does this informally. A fractional CTO takes the role on properly, without the cost of a full-time executive.

What does a fractional CTO do?

A fractional CTO owns the technical decisions and explains them in plain language to the people who are not technical. The work varies with the company’s stage, but it usually covers the areas in the table.

Area	What it looks like in practice
Architecture and build-vs-buy	Choosing the stack, and deciding what to build, buy or leave alone
Suppliers and quotes	Reviewing agency proposals and contracts against your brief
Hiring	Writing the role, interviewing and vetting engineers
Delivery	Setting priorities, reviewing progress, unblocking the team
Security and risk	Checking access, backups and data handling, and reporting to the board
Investor and board questions	Answering technical questions in a raise or a sale

On security, the National Cyber Security Centre publishes a Cyber Security Toolkit for Boards, which includes a download titled “Questions for the board to ask about cyber security”. A fractional CTO can be the person who answers those questions for a board with no technical member.

Engagements come in two broad shapes. In an advisory arrangement the CTO reviews decisions, joins regular sessions and is on call for the big calls. In a hands-on arrangement they run your developers, hiring and suppliers day to day. Our fractional CTO service offers both, and the cost section below prices them.

Do you need a CTO? Signs a fractional one fits

You need a CTO when technical decisions are costing you money or time and nobody in the business can judge them. These are the usual signs:

• Decisions stall. An architecture nobody will commit to, or one developer making every call with nobody able to challenge them.
• A quote you cannot judge. You hold an agency proposal or a contract and cannot tell whether the scope, the price or the timeline is fair.
• Hiring you cannot assess. You are about to hire engineers and cannot tell a strong candidate from a confident one.
• Technical questions are coming. An investor, a buyer or an enterprise customer is about to ask questions about your technology that you cannot answer.
• Nobody owns risk. Cloud costs, outages or security worries keep surfacing and nobody is accountable for them.

If one of these describes you, a fractional CTO is a reasonable fit. If none does, you may need something smaller or something different.

When a different purchase fits better

• One decision, once. A single review does not need a standing arrangement. Our tech consulting service covers technical due diligence from £4,000 and an architecture and roadmap from £8,000. Our guide to technical due diligence explains what a review checks.
• An idea that is not defined yet. A product discovery sprint, from £4,000, turns an idea into a scoped, costed plan before you commit to a build.
• An inherited codebase. If the question is whether to fix or replace a system, rebuild discovery assesses one system for £4,000.
• More building capacity. If the product needs hands rather than direction, staff augmentation puts engineers inside your team, from £4,000 a month per engineer.

Fractional, interim, full-time or technical co-founder?

The five common routes differ in how much time you buy, how you pay and what problem each one solves.

Option	What you get	Best when
Fractional CTO	Senior technical leadership, part-time and ongoing	You need direction rather than extra hands
Interim CTO	A full-time stand-in for a fixed period	A CTO has left and the seat must be covered
Full-time CTO	One person’s whole working week	Technology is the product and it changes weekly
Technical co-founder	A co-owner, paid mainly through equity	You are starting a company and want a partner
Agency or dev shop	A delivery team and its project lead	You know what to build and need it built

An interim and a fractional CTO are often confused. Interim covers a gap and ends when the permanent hire starts. Fractional has no vacancy behind it. It is a different shape of the same role, bought because you do not need a full-time one.

Engaging an individual through their own company raises an employment-status question. GOV.UK says that in most cases the client is responsible for deciding the worker’s employment status. The exception is a small client outside the public sector, where the worker’s intermediary decides (GOV.UK, off-payroll working rules). This is not tax or legal advice, so check your position with an accountant before you sign.

How much does a fractional CTO cost in the UK?

Our fractional CTO service starts from £3,000 a month for the Advisory CTO and from £8,000 a month for the Hands-on CTO. We price by the month rather than the day, so the useful question for any provider, us included, is how many days a month the price buys. Without that answer, two monthly prices cannot be compared.

For market context, ITJobsWatch publishes figures from UK job adverts. At the time of writing (October 2026), the median advertised permanent salary for the Chief Technology Officer job title was £100,000 in the 6 months to 17 Oct 2026. That comes from 59 adverts that quoted a salary, out of 78 permanent CTO adverts, and compares with £120,000 in the same period a year earlier.

The contract equivalent is a median advertised daily rate of £635 for the same period, against £900 a year earlier. That sample is small: 11 adverts quoted a daily rate, out of 14 contract CTO adverts. Treat it as a rough marker only. The figures describe advertised pay for the job title, and we cannot tell from them whether any role is fractional.

The table turns those figures into illustrative annual costs. The workings follow it.

Route	Illustrative annual cost	Basis
Employed CTO	£115,570.90	£100,000 salary plus employer NI and pension
Contract CTO, 4 days a month	£30,480	4 days × £635 × 12 months
Our Advisory CTO	From £36,000	From £3,000 a month × 12
Our Hands-on CTO	From £96,000	From £8,000 a month × 12

The four days a month is our own illustration, chosen to show how a day rate scales. The other rows use published figures and prices.

The workings for the employed CTO

Employer National Insurance for a standard employee is 15% on pay above the £5,000 secondary threshold in 2026 to 2027 (GOV.UK). On £100,000 that is 15% of £95,000, or £14,250. The minimum employer pension under automatic enrolment is 3% of earnings between £6,240 and £50,270 (GOV.UK), which is 3% of £44,030, or £1,320.90. The total is £100,000 + £14,250 + £1,320.90 = £115,570.90, or about £9,631 a month.

That total excludes recruitment fees, bonus, equity, benefits, equipment, management time and cover for holiday and sickness. It is also before any Employment Allowance, which lets eligible employers reduce their annual National Insurance bill by up to £10,500 in 2026 to 2027. A real hire costs more than the table shows.

How to read the table

Read the rows as shapes of engagement rather than a league table. The employed CTO is the only row that buys a full working week. The monthly retainers buy a share of one. If you need most of a week, every week, for years, hiring wins on cost per day. If you need judgement at the moments that matter, the retainer wins on cost per useful decision.

A hands-on arrangement from £8,000 a month adds up to £96,000 over twelve months, which is close to the employed figure. If your need is that large, ask honestly whether a hire is the better answer. We would rather tell you that on the first call than sell you twelve months of it.

For the same method applied to developers, see our guide to software development cost in the UK, which prices developer time against day rates and employer on-costs.

When a full-time CTO is the better answer

A full-time CTO is the better answer when technology is your product and the work fills most of every week. Three situations point that way:

• The product changes weekly. If the architecture, the roadmap and the team all move every week, part-time attention leaves decisions waiting.
• You manage a large engineering team. A growing team needs a leader who is present for the daily friction of delivery.
• Investors or customers expect a named full-time executive. Some do, and meeting that expectation means a full-time hire.

A fractional CTO can still help you get there. A common path is to use one to define the role, run the search and vet the candidates, and then step down as the hire settles in. A few advisory months during a search cost little next to a full-time salary, which makes a better hire worth paying for.

Independent individual or agency CTO?

Some founders prefer an independent individual, and the reason is fair. A CTO who works at a software agency advises on purchases the agency may also sell. We are a software studio that also offers a fractional CTO service, so we have that interest, and you should weigh our advice accordingly.

Whoever you choose, ask these five questions before you sign:

1. Who exactly will do the work, and on which days?
2. Will the recommendations be written down, with the alternatives considered, including buying off the shelf and doing nothing?
3. Does the CTO, or their employer, earn from any supplier or product they recommend?
4. How does the engagement end? Ask about notice, handover notes and who keeps the documents.
5. What would make them tell you that you do not need them?

Keep the advice and the build as separate purchases, with separate scopes and prices. Ours are published separately: a fractional CTO is a monthly service from £3,000, and a bespoke build starts from £15,000. The same discipline applies when you choose a build partner, and our guide to how to choose an AI automation agency lists the questions to ask.

How to get the most from a fractional CTO

A fractional CTO is only as useful as the access and the brief you give them. Five habits make the difference.

Write down what you want decided in the first 90 days. A hiring plan, a costed roadmap and a supplier shortlist are concrete outputs you can check. “Help with tech” is not.

Give access on day one. Repositories, cloud accounts, supplier contracts and the last three quotes you received. Advice built on a description of the system is weaker than advice built on the system.

Keep a decision log. Each entry records the decision, the reasons and the alternatives that were rejected. It is the document your next CTO, your auditor or an acquirer’s reviewer will ask for first.

Use them for decisions rather than tickets. A fractional CTO writing code is an expensive developer. If you need code written, buy engineers separately.

Plan the end at the start. Agree notice, handover and what step-down looks like once things are stable, so the arrangement can end cleanly when it has done its job.

Next step: write down what is stuck

List the three technical decisions that are stuck or about to be made. If at least one involves money, a hire or a supplier, a fractional CTO is a reasonable fit. The Advisory CTO starts from £3,000 a month and the Hands-on CTO from £8,000 a month on our fractional CTO page. The first conversation is a way to find out whether you need either.

If it turns out that you need a single review or a better-defined plan, we will say so and point you to tech consulting or product discovery instead.