US CFO Services. Done right.

A fractional CFO is a senior finance leader who works for your business part-time, on a fixed monthly arrangement, instead of being hired full-time. You get the judgement of a chief financial officer, the forecasting, the fundraising preparation, the board reporting and the strategic calls on pricing and cash, without carrying a six-figure salary on your payroll.

It is worth being clear about what a fractional CFO is not. A bookkeeper records what has already happened. An accountant prepares your statutory accounts and tax returns and keeps you compliant. A fractional CFO sits a level above both: they own the forward-looking work, the model that tells you whether you can afford the next hire, the runway calculation that tells you how many months of cash you have left, and the numbers a board or an investor will scrutinise. Most growing companies need all three functions; the question is whether the CFO layer justifies a full-time appointment yet.

In practice the role covers cash-flow forecasting and scenario planning, a board-ready financial model, budgeting and budget-versus-actual reporting, fundraising and investor diligence support, pricing and margin analysis, and the financial side of hiring and expansion decisions. The work is strategic and recurring rather than transactional, which is exactly why it suits a fixed monthly block of senior time rather than a permanent hire.

You need fractional CFO support when the financial decisions in front of you have outgrown your bookkeeping and your founder instinct, but the workload does not yet justify a full-time finance director. The usual triggers are a fundraise on the horizon, revenue growing fast enough that cash timing becomes a risk, a board that now expects proper reporting, or a founder spending more evenings in spreadsheets than is healthy or wise.

Company size is a useful, objective signal. Under Companies House thresholds for financial years beginning on or after 6 April 2025, a company counts as small (and is generally exempt from audit) if it meets at least two of three tests: turnover no more than £15 million, balance sheet total no more than £7.5 million, and 50 employees or fewer. As you climb through that band, the finance function that worked at startup stage starts to creak, and the audit and reporting obligations that come with crossing it are far easier to meet when someone senior already owns the numbers. The micro-entity floor sits much lower, at £1 million turnover, £500,000 balance sheet and 10 employees, so most businesses considering a CFO are comfortably past it.

If you are not sure whether you have crossed the line from needing an accountant to needing a CFO, that is itself a useful conversation. You can book a free 30-minute call with us and we will tell you honestly which finance layer your business is missing, rather than selling you a tier you do not need yet.

A fractional CFO costs a fraction of a permanent one because you pay for a defined block of senior time each month rather than a full salary, employer National Insurance, pension and benefits. A full-time finance director in the UK is a senior six-figure commitment once total package is counted; a fractional arrangement lets you access the same calibre of judgement for the hours you genuinely need.

At Zmartly the work sits inside fixed monthly pricing of £99, £199 or £499 depending on scope, with one-off project work available for a specific fundraise or model build. There is no hourly meter running and no surprise add-ons, which matters when you are already carrying the cost of growth. Billing is rolling monthly with a 30-day money-back guarantee, so you can scale the support up as the business grows and down if plans change, without an annual lock-in.

The other saving is timing. Hiring a full-time CFO too early means paying for capacity you cannot yet use; hiring one too late means scrambling for clean numbers when an investor or lender appears. A fractional model lets you match senior finance cost to the stage you are actually at, then convert to full-time only when the workload truly demands it.

These terms get used interchangeably, but they describe different commitments. A fractional CFO is an ongoing, part-time relationship: the same senior person stays with your business month after month, building real knowledge of your numbers and strategy. An interim CFO is a temporary full-time placement to cover a gap, for example after a departure or through a transaction, and leaves once the gap is closed.

Part-time CFO usually means the same thing as fractional in everyday use, though some people use it to describe a single employee working reduced hours rather than an external adviser. Outsourced CFO emphasises that the function sits outside your payroll entirely, delivered by a firm rather than an individual on your books. The practical distinction that matters to you is continuity and accountability: you want one named person who owns the forward-looking numbers and stays put, not a rotating queue.

That is the model we run. You work with a single named, ACCA-qualified accountant who owns your financial picture, with replies guaranteed within 72 hours. For UK founders this also means one adviser who understands both your domestic obligations and any cross-border structure, so nothing falls between two sets of books. If you are weighing up whether to bring this in now or wait, our guide on the future of fractional finance sets out where the model is heading and who it suits.