Fractional CFO vs Full-Time CFO: Which Does Your SaaS Need?

The Core Difference

A full-time CFO is a permanent employee — typically hired when a company reaches £10M+ ARR, has a large finance team to manage, or is approaching an IPO.

A fractional CFO works on a part-time retainer — typically 8–20 hours per month. Same strategic expertise, without the overhead of a full-time hire.

For most SaaS and tech founders in the UK between seed and Series B, the answer is almost always fractional — at least to start.

Cost Comparison

• Full-time CFO: £120,000–£200,000 base + pension + benefits + equity. All-in: £180,000–£250,000+/year.
• Fractional CFO: £2,000–£5,000/month retainer. Annual cost: £24,000–£60,000.

The saving is significant — but cost is not the only factor. The right choice depends on your stage and what you actually need.

When a Fractional CFO Is the Right Choice

• You are between £300K and £5M ARR
• You are preparing for a seed, Series A or Series B raise
• You need financial models, board packs, and cash flow forecasting — but not a full finance department
• You want senior strategic input without the commitment of a permanent hire
• You are planning an exit in the next 2–3 years

When a Full-Time CFO Makes Sense

• You are above £10M ARR with complex, multi-entity finances
• You have a finance team of 5+ people who need a permanent leader
• You are preparing for an IPO or very large institutional raise
• Your board requires a permanent CFO as a condition of the deal

What a Fractional CFO Can and Cannot Do

Can do: Financial modelling, cash flow forecasting, board reporting, fundraising support, exit preparation, budgeting, financial data cleanup, investor due diligence.

Cannot do: Manage a full-time finance team day-to-day, handle payroll or bookkeeping, be present in the office five days a week.

A fractional CFO complements your existing bookkeeper and accountant — operating at the strategic layer those roles do not cover.

The Hybrid Approach

Many fast-growing SaaS companies use a fractional CFO during the growth phase, then transition to full-time when the business genuinely needs it. The fractional CFO often helps define the full