The work a fractional CFO does
Financial strategy and planning: building the financial model, running scenarios, advising on capital allocation decisions. Fundraising: preparing materials, running investor processes, supporting diligence. Board reporting: producing monthly and quarterly board packages, presenting results. Senior oversight of finance: managing the controller and bookkeeper, ensuring the financial operation runs.
What they do not do: bookkeeping, transaction categorization, basic reconciliations. These are lower on the value chain and belong with a bookkeeper or junior accountant. A fractional CFO doing bookkeeping is overpriced for the work and underutilized on the work they should be doing.
Typical time commitment is 10-30 hours per month depending on stage and needs. Pre-raise periods bump up to 40+ hours per month temporarily. Post-raise calms back down to steady-state 10-20 hours. The engagement flexes around business activity.
The signals that you need one
The most common signal: you are preparing to raise capital. A fractional CFO for a first institutional raise almost always pays for itself through better preparation, faster process, and often better terms. Without one, founders often fumble the financial story and produce messy diligence.
Another signal: the CEO is spending meaningful time on finance work that is not the best use of their time. Building models, producing board decks, running numbers. A CFO removes this from the CEO's plate, freeing them for product, customer, and team work that only they can do.
A third signal: the company has outgrown intuition-based financial decisions. Past $2-3M in revenue, decisions about hiring pace, pricing, spend prioritization, and capital structure start having material consequences. Without a CFO thinking systematically about these, decisions get made on gut rather than analysis.
Signals you do not need one yet
Pre-revenue companies rarely need a fractional CFO. The work is too uncertain, the decisions too binary. A bookkeeper plus founder oversight is usually enough. Adding a CFO at this stage often creates sophistication theater without real decision support.
Very small operations with stable cash flow and no growth plans do not need strategic finance. A consultant doing $300K/year with no plans to scale does not benefit from a CFO. The work a CFO does has limited applicability to a steady-state lifestyle business.
Companies without clean books do not benefit from adding a CFO yet. Strategic finance on top of unreliable numbers produces unreliable strategy. The sequence that works is: fix bookkeeping first, add controller oversight, then add CFO. Skipping to CFO with messy books creates friction the CFO cannot resolve.
Evaluating fit
Look for specific stage experience. A CFO who has worked with 10 Series A companies understands Series A dynamics better than one who has only worked with mature companies. Pattern matching from similar situations is valuable in an engagement that happens part-time.
Also look for industry experience when it matters. SaaS metrics, service business dynamics, marketplace unit economics, product business inventory management - each has specific knowledge worth having in the CFO seat. Mismatched industry experience produces generic analysis.
Test the engagement with a scoped project before committing to a retainer. Board deck preparation, financial model build, pre-fundraise readiness assessment. A 4-6 week scoped project reveals how they work, how they communicate, and whether they add value. Cheaper than a 12-month commitment to a wrong fit.