What a fractional CFO actually does
A fractional CFO is an experienced chief financial officer who works for your company part time. They own the same questions a full-time CFO owns. How much cash do we have, how long does it last, and what happens to both if we hire, raise prices, or miss a quarter?
Most engagements center on a short list of outputs. The CFO builds and maintains the financial model, sets the budget, reports to the board or investors, and keeps the monthly numbers trustworthy. They also manage the people and systems that produce those numbers, such as a bookkeeper, a fractional controller, and your accounting software.
The work is not data entry. A good fractional CFO spends their hours on decisions. Should you take the term sheet or keep growing on revenue? Can you afford two engineers this quarter? Is the new pricing plan actually improving margin, or just moving revenue around?
Because the role is part time, the best engagements are tightly scoped. You agree on a weekly hours cap, a few standing deliverables, and a monthly review. That structure keeps cost predictable and keeps the CFO focused on the work that moves the business.
Signs your company is ready for a fractional CFO
Most founders wait too long. They run on a bookkeeper and a spreadsheet until a deal, a raise, or a cash scare forces the issue. These are the moments when a part-time CFO pays for themselves.
- You are preparing to raise a round and investors will ask for a model, a data room, and clean historicals.
- Your bank balance is healthy but you cannot say how many months of runway you have at the current burn.
- Month-end close takes more than two weeks, or the numbers change after you have already used them.
- You are about to sign a large customer contract, a lease, or a loan and nobody has stress tested the terms.
- Your board or lender wants a monthly package and you are building it by hand at midnight.
- Revenue is growing but you cannot explain gross margin by product or customer.
If two or more of these sound familiar, the cost of waiting is usually higher than the cost of 8 to 10 hours a week of senior help. A full-time hire is rarely the right next step at this stage, which is why the part-time model exists.
What the first 30, 60, and 90 days look like
Strong fractional CFOs show progress in a clear order. Here is a typical sequence for a company with a bookkeeper in place and revenue under a few million dollars.
Days 1 to 30 are about truth
The CFO reviews the books, the bank and card accounts, payroll, and open contracts. They find what is miscoded, what is missing, and what is owed. By the end of the first month you have a cash position you can trust and a short written list of risks, ranked by dollar impact.
Days 31 to 60 are about the model
With clean actuals, the CFO builds a driver-based forecast. Revenue, hiring, and spend each connect to a small set of assumptions you can change in a meeting. You also get a monthly reporting package that takes minutes to read, not hours.
Days 61 to 90 are about decisions
Now the model earns its keep. The CFO brings scenarios for the choices ahead of you, such as raising capital, adding headcount, or changing pricing. They also set up the operating rhythm, including a monthly close calendar, a budget review, and a board or investor update template you can reuse.
Fractional CFO, full-time CFO, or an outsourced accounting firm
The three options solve different problems. The table below compares them on the points buyers ask about most. Use it to decide which fits your stage, not to find a winner.
| Option | Typical cost | Time to start | Seniority | Commitment | Contract and payment |
|---|---|---|---|---|---|
| Fractional CFO on Side.work | $175 to $300 an hour for the hours you approve, plus a 12, 8, or 5 percent platform fee | Shortlist the same day, start after intro and contract | Senior operator | Weekly hours cap, notice period | One contract, weekly timesheets, one invoice |
| Full-time CFO | Full salary, benefits, and often equity | Months of search | Senior operator | Open ended | Employment terms |
| Outsourced accounting firm | Monthly package fee | Weeks for onboarding | Mixed, often staff level day to day | Annual or monthly agreement | Firm paper and firm invoices |
If you only need bookkeeping and tax filing, an accounting firm is usually enough. If you need someone to own the forecast, the board, and the hard calls, you need a CFO. Many companies pair the two and add a part-time CFO on top of the existing accountant.
A worked monthly cost for a fractional CFO
Costs are easy to estimate. Take the hourly rate, multiply by hours per week, then multiply by 4.33 weeks in an average month. Add the platform fee for your plan.
Say you hire a fractional CFO for 10 hours a week at $220 an hour. That is $220 times 10 times 4.33, or $9,526 a month in specialist fees. On the Growth plan the platform fee is 8 percent, which adds $762. Your total is about $10,288 a month, billed on one invoice for approved hours only.
The specialist keeps 100 percent of their $220 rate. You pay the plan subscription separately, and the fee drops to 5 percent on Scale. See plans and fees for the full breakdown.
Compare that with the alternative. A full-time CFO means a salary, benefits, and a long hiring process even if you only have 10 hours of CFO work a week. If your needs are closer to 5 hours, the same math brings the fee down to roughly half. If you need 20, you are approaching a full-time role and should compare the total honestly.
How hiring works on Side.work
You start by describing the role in plain terms. Pick fractional CFO, enter the hours per week you want, and set a budget range. Side.work returns a ranked shortlist of verified profiles, each with a weekly availability bar and a rate, so you can see who can actually fit your schedule.
Every profile is checked for a work email domain, a LinkedIn profile, live portfolio links, and payout identity. Specialists also confirm that their side work does not conflict with their employment terms. That removes a common source of surprises.
When you find someone promising, you send an intro. After a call, you sign a contract with a weekly hours cap and a notice period. A standard NDA and IP assignment are attached by default. Each week the specialist submits a timesheet, you approve the hours, and you pay one invoice made of approved hours plus the platform fee. The full flow is on the how it works page.
What to ask in the first call
Fit matters more than résumé length. Use the first call to test how the person thinks, not just where they have worked.
- Walk me through a time you inherited messy books. What did you fix first, and why?
- What would you want to see in my numbers before you give me a forecast?
- How do you report to a board, and can I see a sample package with the names removed?
- Which parts of the work do you hand to a bookkeeper or controller, and which do you keep?
- How many other clients do you carry, and how fast do you reply during a close week?
- What would make you say this engagement is not working?
Listen for specifics. Strong candidates name tools, timelines, and tradeoffs. Weak ones stay abstract. If your main gap is hands-on accounting, you may do better starting with a fractional controller and adding a CFO later.
Mistakes that make a fractional CFO engagement fail
Most failed engagements share the same few causes, and all of them are avoidable. The first is a vague scope. If the contract says only that the CFO will help with finance, both sides will drift. Write down three or four standing deliverables, such as the monthly package, the forecast update, and the board deck, and agree on dates.
The second mistake is hiding the mess. A CFO can only help with what they can see. Give access to the bank, the accounting file, payroll, and key contracts in the first week. Founders who share the ugly parts early get answers in weeks. Founders who wait pay for months of guessing.
The third mistake is hiring for the wrong problem. If your books are a year behind, you need accounting cleanup before you need a forecast. Start with a fractional controller, or ask the CFO to scope the cleanup as the first phase.
The fourth is treating the CFO as an assistant. The value is judgment. Bring them into pricing, hiring, and contract decisions early, not after they are made. A short weekly call and a shared document of open questions will do more than any tool.
Finally, review the engagement every quarter. Ask whether the hours match the work, whether the deliverables still make sense, and whether the CFO has a plan to reduce your need for them over time. A good one will, because the best outcome is a finance function you can run with fewer hours.