Most founders frame this as a cost question. It should not be.
The cost comparison is obvious — a fractional CFO at 6 days per month costs £10,000–£20,000 per month; a full-time CFO at £200,000 salary costs £25,000+ per month in total employment cost, plus notice period, equity, and the full-time commitment risk. On cost alone, fractional almost always wins at growth stage.
But that framing misses the more important question: what does your business actually need? A fractional CFO is the wrong answer for some businesses — and a full-time CFO is the wrong answer for others. Getting this decision right matters more than saving money on a salary.
What each model actually provides
Before comparing them, it is worth being clear about what each option genuinely provides — because both are frequently misrepresented.
A full-time CFO is a senior executive with full leadership accountability, 100% of their professional time, and the ability to be present in the business every day. They own the finance function completely, hire and manage the finance team, attend every board and leadership meeting, and are available for every unplanned financial conversation that arises.
A fractional CFO is an experienced senior leader who works with your business on a defined part-time basis — typically 4–10 days per month. They attend board meetings, manage investors, own deliverables, and provide strategic financial leadership — but they are not available every day, and they work with other clients simultaneously.
The important nuance: a good fractional CFO is not less capable than a full-time CFO. They are the same calibre of person, in a different commercial arrangement. The practical limitation is availability and bandwidth — not seniority or competence.
The comparison
| Factor | Fractional CFO | Full-Time CFO |
|---|---|---|
| Cost (UK) | £10,000–£20,000/month Typically 4–10 days/month |
£20,000–£35,000+/month Salary + NI + pension + benefits |
| Availability | Defined days per month; contactable outside agreed days for urgent matters | Full-time; available every day |
| Commitment risk | Low — typically 1–3 month notice; easy to adjust scope | High — 3–6 month notice period; significant disruption if wrong hire |
| Equity | None — day rate or retainer only | Often 0.25–1.5% equity at growth stage |
| Speed to operational | Fast — experienced operators onboard quickly; contributing from week 2–3 | Slower — 1–3 month hiring process; 1–3 month ramp |
| Breadth of experience | Often broader — works across multiple businesses and sectors simultaneously | Depth in fewer businesses over time |
| Team management | Can oversee and hire, but less suited to daily people management | Full accountability for the finance team |
| Cultural integration | Present but not embedded; can feel more external | Full cultural member of the leadership team |
| Best for | £1M–£30M revenue; pre-Series A to Series B; specific project needs | £20M+ revenue; post-Series B; complex multi-entity operations |
When fractional makes more sense
A fractional CFO is typically the right answer when:
- The business is below £20M–£30M in revenue and the finance complexity does not yet justify a senior full-time salary
- There is a specific event — a fundraising round, a financial model build, an exit process — that requires senior capability for a defined period
- The business needs CFO-level strategy and investor management, but already has a Finance Manager or Controller handling day-to-day operations
- The CEO needs to be freed from finance responsibilities but is not ready to commit to a permanent hire
- Speed matters — a fractional CFO can be operational within weeks; a full-time hire takes months
- Flexibility matters — the scope can be adjusted up or down as the business evolves
When full-time makes more sense
A full-time CFO is the right answer when:
- The business has reached a scale — typically £20M–£30M+ revenue or post-Series B — where the finance function is large and complex enough to require full-time senior leadership
- The CEO needs a true peer on the leadership team who is present every day and embedded in every significant business decision
- The business is managing a large finance team (5+ people) that needs daily management and development
- The operational complexity — multi-entity group structures, complex revenue recognition, large treasury operations — requires full-time senior finance ownership
- Regulatory obligations (FCA, listed company requirements) mandate specific senior finance presence
A third option worth considering
Many businesses find that the right answer is neither purely fractional nor purely full-time — it is a combination. A fractional CFO to provide strategic leadership and investor management, alongside a Finance Manager or Controller in-house handling day-to-day operations and team oversight.
This model gives the business senior strategic capability at a fraction of the cost, while maintaining operational finance continuity. It also provides a natural succession path — when the business is ready for a full-time CFO, the Finance Manager is already in place and well-developed.
A practical note: If you are undecided, a fractional engagement is almost always the lower-risk starting point. It is significantly easier to transition from fractional to full-time than to unwind a full-time hire that turns out to be premature or wrong. The cost of a bad full-time CFO hire — in salary, disruption, notice period, and lost time — is substantial.
The decision in practice
If your business is below £20M revenue, approaching a fundraise, operating in fewer than three jurisdictions, and does not yet have a finance team of more than 2–3 people — a fractional CFO is almost certainly the right answer.
If your business is above £30M revenue, has a finance team of 5+ people, is post-Series B, and needs a true peer to the CEO on the leadership team every day — a full-time CFO is probably the right answer.
If you are somewhere in between, the fractional model with an in-house Finance Manager is worth considering seriously — it provides the strategic capability you need without the cost and commitment of a full-time senior hire before the business is ready for one.
Not sure which is right for your business?
Start with a conversation. Most engagements begin with a 30-minute call to understand where the business is and what it needs — with an honest answer about whether fractional is the right answer or whether a full-time hire makes more sense at your stage.
Schedule a Call