The short answer
At least five labels circulate for external CFO capability. Behind them sit only two models:
- Ongoing financial leadership, part-time. Fractional CFO, outsourced CFO, part-time CFO and CFO as a Service all mean essentially this.
- Filling a role on a fixed term, usually full-time. That is interim management, often as an interim CFO.
The dividing line runs not between the labels but between ongoing and partial on one side and fixed-term and whole on the other. Sort that out and offers become comparable; before that, they are not.
The terms at a glance
| Term | Origin | Model it means | Where it mostly appears |
|---|---|---|---|
| Fractional CFO | US usage, literally a “fractional” CFO | Ongoing part-time | Startup and VC circles, English-speaking providers |
| Outsourced / external CFO | General business usage | Ongoing part-time | Mid-market, classic consulting |
| Part-time CFO | Plain description | Ongoing part-time | Less common, but the most precise |
| CFO as a Service | Borrowed from software vocabulary | Ongoing part-time, usually modular | Providers that switch individual services on and off |
| Interim CFO | Established, defined by industry associations | Fixed-term, usually full-time | Providers, associations, corporate groups |
Occasionally virtual CFO, CFO on demand or the German CFO auf Zeit join in. They add nothing.
The proliferation is not accidental: a new label makes a familiar offering look new. For buyers it mostly means friction – four enquiries to four providers, four different words for the same service, and four proposals that cannot be laid side by side.
The one dividing line that matters
| Question | Ongoing part-time | Interim |
|---|---|---|
| Trigger | The function is needed, but not full-time | A role is vacant or a specific project is due |
| Time commitment | A few days a month up to several days a week | Mostly full-time or close to it |
| Duration | Ongoing, scope adjustable | Fixed term; via providers 7.1 months on average |
| Billing | Monthly retainer | Day rate |
| End | Open, with a notice period | Defined from the outset |
| Contract question | Usually uncritical, because there is no integration | Critical when purely bridging a vacancy |
The last row is the one that gets overlooked and costs the most. Bridging a regular position one-to-one sits closer to German temporary staffing law than a proposal quoting a day rate suggests – with consequences that fall mainly on the client company. The detail is in the piece on contract forms and bogus self-employment.
What the two models cost
| Model | Billing | German market range |
|---|---|---|
| Fractional / outsourced CFO / CFO as a Service | Monthly retainer | €2,500–15,000 per month |
| Interim CFO, head of finance | Day rate | €1,400–2,500 per day |
| Interim CFO in restructuring or a corporate group | Day rate | from €3,000 per day |
| Permanent hire | Fully loaded annual cost | €140,000–300,000 per year |
Within the retainer, the range moves with scope: a few days a month for sparring and reporting review at the lower end, two to three days a week with de facto financial leadership at the upper. On interim assignments, going through a provider typically adds 25 to 35 percent to the day rate.
The rule of thumb that settles the model question: as long as the monthly retainer stays below roughly 12,000 euros, it is cheaper than the fully loaded cost of your own position. Above that a permanent hire pays off – provided the role can actually be filled. The full calculation with a worked example is in the piece on interim management in the finance department.
How to spot a relabelled offering
The term is everywhere, the model nowhere. If a page says “fractional CFO” ten times but never how many days a month that means, the actual information is missing.
No price, no range, no reference point. “On request” is unusual for a monthly retainer. A range with an explanation of what moves it is the norm among providers who really run the model.
Interim and part-time are blurred together. Selling both as the same thing means either the model has not been thought through or the contract question is being pushed onto the client.
Nothing is said about the end. Ongoing part-time work needs a notice period and adjustable scope in the proposal; interim needs a defined end and a handover.
The scope stays a list. “Controlling, reporting, planning” is a heading. What is delivered monthly and what is billed on top is the answer.
Which term is useful when
For your own search, choose the word your counterpart uses. In startup and investor circles fractional CFO lands well; in the German mid-market externer CFO is understood immediately while the English term invites questions. CFO as a Service signals that services are modular. Reserve interim CFO for cases where a genuinely fixed-term appointment is meant – otherwise you get day-rate proposals for a job that is not one.
For a tender the label matters least. What counts: which outcomes have to exist after 90 days, how many days a month are budgeted for them, and whether the arrangement is meant to be ongoing or fixed-term. With those three, proposals become comparable regardless of the word on the cover page.
Frequently asked questions
What is a fractional CFO?
An experienced finance leader who works for a company on an ongoing but partial basis – typically a few days a month up to several days a week. The term comes from the US market; outsourced CFO, part-time CFO and CFO as a Service describe essentially the same model.
What is the difference between a fractional CFO and an interim CFO?
A fractional CFO provides ongoing part-time support, billed as a monthly retainer, with an open end and adjustable scope. An interim CFO bridges a specific vacancy, usually full-time, billed by the day, with an end defined from the outset. Interim assignments placed through providers run 7.1 months on average per the DDIM market study 2026.
What does a fractional CFO cost in Germany?
The market range for monthly retainers is 2,500 to 15,000 euros. A few days a month for sparring and reporting review sits at the lower end; two to three days a week with de facto financial leadership at the upper.
Is an outsourced CFO the same as CFO as a Service?
In effect, yes. “CFO as a Service” additionally emphasises that the offering is modular – accounting, reporting, planning, liquidity and investor communication can be switched on and off individually. The underlying model in both cases is ongoing financial leadership, part-time.
When does a permanent CFO position make more sense?
As a rule of thumb from around 12,000 euros in monthly retainer – at which point the model approaches the fully loaded cost of an in-house position, roughly 140,000 to 190,000 euros a year in the German mid-market and well above that in corporate groups. Provided the role can be filled and the workload genuinely occupies a full-time person.
Which term should I use in my enquiry?
The one your counterpart understands – fractional CFO in startup circles, externer CFO in the German mid-market. More important than the word are three data points: which outcomes have to exist after 90 days, how many days a month are budgeted, and whether the arrangement is ongoing or fixed-term.
Further reading
- Interim management in the finance department – roles, how an assignment runs and the first 90 days.
- Interim CFO contracts in Germany – service contract, temporary staffing and bogus self-employment.
- How to find an interim CFO – the four routes to a provider and twelve selection criteria.
- CFO as a Service at nugrow – how the modules are tailored to individual companies.
Sources
Monthly retainers and fully loaded cost of a permanent hire: MRH Beratung. Day-rate ranges by role and provider margin: Interim Profis and Effizienzbuchhalter. Average day rate and assignment length: DDIM market study 2026. CFO median salary: StepStone salary data Germany. All figures as of 2026; they describe the market, not the terms of any individual provider.
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