The core difference
The two terms get used interchangeably, but they describe different engagements. The split comes down to time commitment and intent.
| Fractional | Interim | |
|---|---|---|
| Hours | Part-time, 10-20/week | Full-time, 40+/week |
| Clients at once | 2-4 | 1 |
| Duration | Ongoing, 3-12+ months | Fixed, until a permanent hire |
| Why hired | Need the role, not full-time | Fill a sudden gap |
| Mindset | Build systems that outlast them | Stabilize and hand off |
When you want fractional
You need executive-level judgment but not an executive-sized seat. A $3M company needs CFO thinking 12 hours a week, not 40. Fractional fits when the work is real but doesn't fill a full week, and when you want someone who builds repeatable systems and stays for the long arc rather than a single transition.
When you want interim
A full-time executive just left, a transaction is mid-flight, or you need a steady hand running the function full-time until you hire permanently. Interim is full-time, single-company, and time-boxed. The interim exec's job is to stabilize the function and hand it off cleanly — not to embed for years.
Where they overlap
Both are senior, both are temporary by design, and the same person often does both depending on the engagement. Employers sometimes label a role "interim" when there's a defined end date tied to a full-time hire, even if the hours are part-time. Read the hours and the duration, not just the title.