Interim day rates vary by function, and the comparison that matters is not the day rate but the month at which a permanent hire — including search fee, notice and ramp-up — becomes cheaper. Below that point, interim is cheaper as well as faster.
What does an interim CFO cost?
As a day rate, more than the equivalent permanent salary implies — which is the figure most comparisons stop at, and the reason interim looks expensive to anyone comparing it to a monthly payroll cost.
As a six-month total against the real cost of hiring permanently, including search fee, notice period and ramp, the comparison changes considerably. Both numbers are true and they support opposite conclusions, which is why the decision is better framed as when to switch from interim to permanent than as which is cheaper.
What sets the day rate?
Scarcity of the specific experience rather than seniority alone. Someone who has carved out a business unit at this scale prices above a more senior executive who has only ever run a going concern, because the pool of people who have done the specific thing is small.
Engagement length compresses the rate. A three-month commitment prices below a six-week one for the same person, which makes short urgent engagements the most expensive way to buy the same capability — the same curve independent consultant rates follow.
Where does interim stop being cheaper?
At the point where the cumulative day rate exceeds salary plus search fee plus the cost of the vacancy that preceded the permanent hire. That is later than most boards assume because the search fee and notice period are frequently left out of the comparison.
Below the crossover, interim is cheaper and faster. Above it, the permanent hire wins on cost and on the long-horizon ownership an interim is not being paid to provide.
The crossover also moves with how quickly the permanent search can realistically run. Where the role is scarce and the search will take six months, the interim period is longer by definition and the comparison shifts in its favor; where the market is deep, the reverse. Calculating a crossover without a realistic search timeline produces a number that flatters whichever option was already preferred.
Is fractional different from interim?
In commitment more than in rate. Interim usually means full-time for a defined period covering a gap; fractional means part-time on an ongoing basis where the company needs the capability but not the headcount.
The confusion matters when scoping. A fractional arrangement priced as if it were interim tends to under-buy availability, and the executive ends up rationing time across clients in a way nobody planned for.
Availability is the other thing to pin down in a fractional arrangement. Two days a week can mean two fixed days or two days spread across five, and the difference decides whether the executive can be in the meetings that matter. It is a scheduling question that determines the value of the engagement more than the rate does.
What do you get for it?
Capability without the hiring cycle, and someone who has done the specific thing before rather than someone who will learn it. For a carve-out, a systems migration or a first-time close, that is most of the value.
What you do not get is long-horizon ownership. An interim optimizes for the period they are accountable for, which is correct and is also why the crossover matters.
The scope of what an interim will take on is also worth agreeing explicitly, because it is where expectations diverge most. An interim brought in to stand up a function will usually decline to make decisions that bind their successor, which is correct behavior and frequently reads as reluctance to the board that hired them. Naming the boundary at the start prevents the second half of the engagement being spent negotiating it.