The monthly retainer, and what sets the tier
For most seed-stage founders the number lands between $1,000 and $3,000 a month for five to ten hours a month. For a hyper-growth or operationally complex business it moves to $5,000 to $10,000 a month for five to ten hours a week.[1] The jump between those two tiers is not seniority. It is frequency. The second business needs someone in the numbers every week, not someone reviewing a pack once a month.
What moves you up a tier is complexity, not revenue. A single-product SaaS business can run a long way on a light retainer, while a deep tech or robotics business with inventory, grants and hardware milestones needs a finance professional sooner.[2] Price the arrangement against how many moving parts the business has, not against the ARR line.
| Typical monthly cost | What that tier is buying | |
|---|---|---|
| Seed, low complexity | $1,000 to $3,000 a month, 5 to 10 hours a month | A monthly review, a cash and runway view, and someone to sanity check the raise model. The founder is still leading the finance function. |
| Growing, more moving parts | Middle of the range, weekly or fortnightly cadence | Board pack input, forecasting discipline and investor reporting, with a bookkeeper or outsourced accountant handling the transactional work underneath. |
| Hyper-growth or operationally complex | $5,000 to $10,000 a month, 5 to 10 hours a week | Close to a part-time executive. This is usually the tier where the arithmetic starts pointing at a permanent Head of Finance instead. |
How it compares to a full-time CFO
This is the comparison every founder wants, and the honest version is that they are not really substitutes. A permanent CFO at late Series A in Australia runs $275k to $325k base plus equity, and Series B moves to $325k to $375k.[3] On top of base you carry superannuation, leave, payroll tax and the recruitment cost, so the real annual number is meaningfully above the salary line. A $3,000 a month retainer is $36,000 a year against that.
But the comparison flatters the retainer, because you are not buying the same thing. A part-time CFO gives you judgement on the decisions that matter. They do not build your finance function, own your close, sit across your systems or lead a team. Most businesses in the middle actually need a Head of Finance, not a cheaper CFO. When founders ask whether they need a CFO or a Head of Finance, the honest answer for most, most of the time, is still a Head of Finance.[4]
If the real gap is ownership rather than advice, the Head of Finance band is the number to be comparing against, and I set it out here.
How long the arrangement should last
Fractional finance buys you 18 to 24 months of proper financial visibility before a full-timer is needed, and that is roughly the window a part-time CFO is genuinely relevant to a startup.[5] Inside that window it is excellent value. Past it, the economics quietly invert.
The trap is staying on it too long. It usually shows up at Series A, when the finance function becomes the bottleneck on hiring, board reporting and capital planning.[6] At that point you are paying a retainer for advice while the actual work piles up around it, and the retainer starts creeping upward to cover the gap. That is the moment to stop extending and start hiring.
What a part-time CFO cannot do for you
A part-time arrangement is capacity you rent. It is not accountability you own. The thing you notice when someone properly owns finance inside the business is that reporting gets clearer, forecasts become more believable, board prep gets less chaotic, cash conversations get more accurate, and hiring plans get properly tested before they become commitments.[7] Almost none of that comes from someone dialling in for six hours a month.
The other thing worth naming: part-time roles rarely turn out to be genuinely part time, and people often end up doing far more hours than the arrangement pays for.[8] That is fine for a while. It is not a structure you should be relying on two years in, because it depends on someone else's goodwill rather than on a role that is properly resourced.
If you are trying to work out whether the next hire is a retainer, a Head of Finance or a real CFO, I set out the signals here.
What I do with founders on a retainer
I do not sell fractional CFO services and I place permanent finance leaders, so my interest here is straightforward. When a founder is genuinely too early for a permanent hire, I introduce them to a good fractional CFO and take no fee for it. I have done that inside four hours before.[9] A founder who needs a fractional CFO today is often building something that will need a full-time hire in eighteen months, and they remember who was useful before there was anything in it.[10]
My lane is the hire on the other side of that: the first finance hire at 10 to 20 heads and $5 to $10 million ARR or less, and the first CFO at 50 plus heads and $10 million plus ARR, in Australian VC-backed startups and scale-ups. If the retainer is starting to strain, that is the conversation to have.
Common questions
How much does a part-time CFO cost in Australia?
For most seed-stage founders the arrangement runs $1,000 to $3,000 a month for five to ten hours a month. For a hyper-growth or operationally complex business it moves to $5,000 to $10,000 a month for five to ten hours a week. What moves you between those tiers is complexity and cadence rather than revenue: a business that needs someone in the numbers weekly pays weekly money.
Is a part-time CFO cheaper than a full-time one?
On the invoice, clearly yes. A permanent CFO at late Series A in Australia runs $275k to $325k base plus equity, plus superannuation, leave, payroll tax and recruitment cost. A $3,000 a month retainer is $36,000 a year. But you are not buying the same thing. A part-time CFO gives you judgement on decisions. They do not build the function, own the close, run the systems or lead a team, and for most businesses in the middle the real answer is a Head of Finance rather than a cheaper CFO.
How long should a part-time CFO arrangement last?
Fractional finance typically buys 18 to 24 months of proper financial visibility before a full-timer is needed, and that is about the window where a part-time CFO is genuinely the right structure for a startup. The trap is staying on it too long. It usually surfaces at Series A, when the finance function becomes the bottleneck on hiring, board reporting and capital planning. Once the retainer is creeping up to cover the gap, you are paying for advice while the work piles up.
What does the retainer not cover?
Ownership. A part-time arrangement is rented capacity, not accountability inside the business. When someone properly owns finance, reporting gets clearer, forecasts become more believable, board prep gets less chaotic, cash conversations get more accurate and hiring plans get tested before they become commitments. Very little of that comes from six hours a month. Part-time roles also rarely turn out to be genuinely part time, and relying on that goodwill long term is a structural risk.
References
- Tom Hunter on typical fractional finance costs in Australia: $1-3k per month for 5-10 hours per month at seed stage, scaling to $5-10k per month for 5-10 hours per week for hyper-growth or operationally complex businesses.
- Tom Hunter on complexity driving timing: a single-product SaaS business might not need a first finance hire until Series B and can rely on a fractional CFO for a long time, while complex deep tech businesses such as robotics need a finance professional sooner.
- Story Recruitment 2026 finance leadership salary bands: late Series A CFO $275-325k plus equity, Series B CFO $325-375k plus equity.
- Tom Hunter on the CFO versus Head of Finance question: the honest answer for most founders, most of the time, is still a Head of Finance.
- Tom Hunter on the fractional window: fractional finance can provide 18-24 months of proper financial visibility before a full-timer is needed, and a fractional CFO is typically relevant to a startup for a finite period of 18 to 24 months.
- Tom Hunter on the fractional trap: staying with it too long, particularly when a Series A business finds its finance function is a bottleneck on hiring, board reporting and capital planning.
- Tom Hunter on what changes when someone properly owns finance in a startup: clearer reporting, more believable forecasts, less chaotic board prep, more accurate cash conversations, and hiring plans properly tested before they become commitments.
- Tom Hunter on part-time roles: they are rarely actually part time, with individuals often ending up doing far more hours than they need to.
- Story Recruitment: Tom Hunter introduced a founder to a fractional CFO within four hours, with no fee attached.
- Tom Hunter on the long game: a founder needing a fractional CFO today might be building something that will require a full-time hire in 18 months, and they remember the conversation when the timing is right.