"We need a CTO." We hear this every quarter. It's rarely wrong — but almost always mis-framed. What companies need is the work of a CTO: technical arbitration, team structure, security, product scoping. Not necessarily a full-time CTO.
The raw math
A senior CTO in France, in 2026: median salary between €100 and €140k gross for an SMB, €150 to €200k for a scale-up. Add employer charges (~45%), bonuses, stock, and above all hiring cost (headhunter: 20 to 30% of annual salary, i.e. €25 to €60k; 4 to 8 month delay during which nobody does the work).
Real employer cost, year 1: €150 to €260k.
A fractional CTO at 2 days per week, €1,000 excl. VAT day rate, 44 active weeks (net of holidays): €88k excl. VAT / year. That's ~3× less for 40% of the time — so about 80% of the value for most teams under 15 people.
The math is not magic. It rests on three facts:
- A full-time CTO on a 5-person team spends half their time on non-CTO work: meetings, email, coordination, tasks that could be delegated.
- Role value is concentrated on a few moments: architecture decisions, structural tool choices, product/tech arbitration, security reviews, hiring decisions. 2 well-placed days per week cover 80% of these.
- Non-decision cost (tech debt, bad infra choice, neglected security) is far worse than a part-time CTO. The real comparison isn't "fractional vs full-time," it's "fractional vs nobody."
Signals it's time
Without claiming exhaustiveness — here are the alerts that lead us to say "yes, you need a fractional CTO now":
- Tech team grew from 2 to 6 people and the founder now spends 80% of their time settling technical debates they no longer have time to properly investigate.
- Security is a blind spot — no written GDPR policy, no posture audit, no disaster recovery plan, and the question "what happens if our database is compromised this weekend?" has no clear answer.
- A growing client is demanding things that scare you: SLA, audit, certification, 200-line cyber questionnaire. You want to sign, but you need someone to own the technical response and commit to it.
- A structural choice is approaching: cloud migration, SaaS overhaul, AI project, mobile platform. Getting it wrong costs 6 to 24 months.
- A funding round is coming and you know a serious VC will require technical due diligence. Anticipate: better a fractional CTO who prepares the ground than discovering in due dill' that 18 months of debt have accumulated.
How it actually works
At MAG&Cie, the format is explicit:
Scoping (1 to 2 weeks). Half a day of audit, another to align on priorities. Deliverable: a 3 to 5 page note listing what the fractional CTO will commit to over the next 3 months, what they won't take on, and how value will be measured.
Rhythm (mission). 2 days per week by default, flexible 1 to 3. Two fixed rituals: a 45-minute weekly (leader + tech lead + CTO), a 2-hour monthly architecture review. The rest — code reviews, async one-on-ones, executive committee attendance — fits into reserved slots.
Quarterly measurable deliverables. This isn't hourly work. We commit to things: "secure the infra per ANSSI checklist by Q2," "hire the backend lead by Q3," "deliver the 2026 roadmap board-validated by Q1." If deliverables don't move, the mission is renegotiated.
Exit. Three exit paths: (1) transition to an in-house CTO we co-recruited — the preferred outcome, ~40% of missions, (2) mission renewed on a new project — ~35%, (3) load drop to 1 day/week or less in pure advisory — ~25%.
What it isn't
Three common confusions to clear:
Not a consultant. A consultant delivers a report, leaves, lets the client sort out execution. The fractional CTO makes decisions in the client's name, signs choices, engages responsibility. They're in the weeklies, not outside.
Not a disguised senior developer. The fractional CTO codes little (sometimes not at all). Their value is upstream: architecture, tool choices, arbitration, team structure. If they code, it's architecture prototypes or unblocking, not production roadmap work.
Not exclusive. An experienced fractional CTO has 2 to 4 clients in parallel. That's what lets them keep a sustainable day rate AND stay in touch with multiple stacks / sectors. Checking there's no frontal conflict (direct competitor) is normal; demanding exclusivity is buying a disguised full-time.
The real risk
It's not paying a CTO who only works 2 days. The real risk is:
- Taking a fractional CTO too early — 2-person team without a shipped product, value isn't there. A one-off consultant or an advisor board is enough.
- Taking one too late — 18 months of accumulated tech debt, the team has settled into bad reflexes, correction cost is a rewrite.
- Not scoping deliverables — a fractional CTO without measurable objectives quickly becomes an observer, not a leader. Responsibility falls on the client as much as the CTO.
Our concrete offer
At MAG&Cie, we offer two formats:
- CTO partnership — 2 days / week, 6 to 24 month engagement, €1,000 excl. VAT day rate or monthly flat fee on quote.
- One-off strategic missions — 5 to 15 days for scoping, an audit or a crisis response.
Want to see if it can fit? The 30-minute meeting is free and no commitment. Together we look at whether you really need a fractional CTO — or if a one-off project is enough.
The best fractional CTO is the one who tells you no when you don't need one.