Most owners ask the question backwards. They ask whether to hire a fractional CFO or a full-time one, when the real question is how much CFO the business actually needs this year — measured in days, not titles.
A full-time CFO is a $250,000 to $400,000 decision once you load salary, bonus, equity, and benefits. For a business doing $5M to $50M, that hire is almost always senior judgment you'll underuse. The work that genuinely needs a CFO — the financing conversation, the board pack, the model behind a hiring decision — doesn't fill five days a week at that size. It fills one to four days a month. The rest of the week, a $350K executive is doing controller work, or worse, waiting for something CFO-shaped to happen.
What you're actually buying
A CFO's value isn't hours. It's the quality of a handful of decisions a year: when to raise and when not to, what a term sheet really costs, whether the business is sellable and what to fix before it is, where the next dollar of capital should go. You're buying judgment on the questions that are too big for the controller and too consequential for instinct.
Fractional works because that judgment doesn't come in a daily dose. A senior operator who has sat in the seat can be in the room for the decisions that matter and out of the building for the ones that don't. The trade is real: you don't get someone walking the floor every day or owning the finance team full-time. You get the senior layer, scaled to how often the business actually needs it.
The revenue band, roughly
No threshold is clean, but the pattern holds.
- Below ~$5M: Usually no CFO yet, fractional or otherwise. What's needed is clean books and a controller-level close. A fractional CFO here is often answering questions the business isn't asking yet.
- ~$5M to $50M: The fractional sweet spot. The questions have gotten bigger than the in-house team can answer — financing, FP&A, board reporting, maybe an exit on the horizon — but not frequent enough to justify a full-time hire. One to four days a month covers it.
- Above ~$50M, or through a transaction: The math starts to flip. When CFO-level decisions are a daily occurrence, when there's a finance team that needs managing, when you're mid-raise or mid-sale with diligence running every day — the value of someone in the building full-time begins to exceed the premium of paying for it.
The signals that you've outgrown fractional
The honest version of this article names the exit. You should hire a full-time CFO — and let a fractional one go — when:
- CFO-level questions are landing weekly, not monthly, and a bi-weekly call can't keep up.
- You have a finance team of three or more that needs day-to-day leadership, not just a senior reviewer.
- You're in a sustained, high-frequency phase — an active raise, a live M&A process, a turnaround — where the work genuinely is full-time for a stretch.
- The business has crossed the point where a CFO's comp is a rounding error against the decisions they influence.
A fractional CFO worth hiring will tell you when you've hit these. We'd rather hand a client to a full-time hire at the right moment than hold an engagement past its usefulness. The relationship is the asset; stretching it isn't.
What fractional can't do
It's worth being plain about the limits. A fractional CFO isn't there for the unscheduled crisis on a Tuesday afternoon unless you've bought on-call time. They won't absorb the culture of the finance team or be the face of finance to every employee. They can't substitute for a controller — different job, different cadence. Fractional is the senior judgment layer, not a full-time presence at a discount. When you need the presence, you need the hire.
So which one?
If you're between $5M and $50M, the questions are getting bigger, and a CFO's week wouldn't be full — fractional is almost certainly the right call, and the cheaper one by a wide margin. If CFO-level work is a daily reality and you have a team to lead, start the full-time search and don't let the retainer talk you out of it.
The wrong answer is the one most owners default to: no CFO at all, decisions on instinct, until a financing or a sale arrives and the infrastructure isn't there. Either dose of senior finance beats that.
If you're not sure which side of the line you're on, that's exactly the conversation a discovery call is for — and we'll tell you honestly if the answer is "not yet" or "you've outgrown us."