A fractional COO works part-time on an ongoing basis (1–2 days a week, 3–12 months) and builds the systems your team owns going forward. An interim COO works full-time for a defined window (3–9 months) to backfill a vacancy or run a specific project. Different commitments, different prices, different outcomes. Pick the wrong one and you’ll either underspend on a real problem or massively overpay for a part-time need.
The one-line difference
- Fractional COO. Part-time, ongoing, building. 1–2 days a week. Stays for as long as you need them, typically 3–12 months.
- Interim COO. Full-time, time-boxed, holding the seat. 5 days a week. Leaves on a defined date.
If you’re confused which one you need, the question to ask yourself is: am I trying to build the operational layer, or am I trying to keep a full-time COO seat warm?
Fractional COO, in detail
Use a fractional COO when:
- You’ve never had a COO and you need someone to build the operational infrastructure from the ground up.
- You can’t justify a full-time COO at £140K+ at your current scale (typically under £10M revenue).
- The role is internal (process, KPIs, contracts, team) rather than externally-facing.
- You want optionality to convert to full-time later, or to scale down to advisory once the systems are in place.
Standard engagement looks like:
- 1–2 days per week, embedded with the team.
- 3-month minimum, most run 6–12 months.
- Monthly retainer (£3,500–£8,000 in the UK).
- Hands-on building: process design, KPI dashboards, contract review framework, sales-to-delivery alignment.
- Trains 1–2 team members to own the new systems on exit.
Full breakdown: What Is a Fractional COO?.
Interim COO, in detail
Use an interim COO when:
- Your full-time COO has just left and you need someone to hold the seat while you recruit (typically 4–9 months).
- You’re running a specific full-time project (integration after acquisition, major transformation programme, regulatory remediation) with a fixed end date.
- The role is largely externally-facing: investors, regulators, key customers expect to see a senior operator in the seat full-time.
- Your scale already justifies a full-time COO (typically £10M+ revenue, 80+ people).
Standard engagement looks like:
- 5 days a week, in the role, often with a formal employment-like contract.
- 3–9 month commitment, defined start and end date.
- Daily rate (£800–£1,500/day in the UK) or fixed monthly fee (£15,000–£30,000/month).
- Holds the existing operational machine together while you recruit the permanent hire.
- Hands over to the incoming full-time COO at the agreed date.
Side-by-side comparison
| Factor | Fractional COO | Interim COO |
|---|---|---|
| Time commitment | 1–2 days a week | 5 days a week |
| Engagement length | 3–12 months | 3–9 months |
| Cost (UK) | £3,500 – £8,000/month | £15,000 – £30,000/month |
| Annual equivalent | £40K – £100K | £180K – £360K |
| Primary purpose | Build the operational layer | Hold the seat / backfill a vacancy |
| Best fit (revenue) | £500K – £10M | £10M+ |
| Externally-facing? | Internal only | Often externally-facing |
| End state | Team owns the systems; advisor steps out | Full-time hire takes over |
When you actually need both
Sometimes the right answer is “both, sequentially.” Two common patterns:
Pattern 1: Bridge to full-time. You’ve decided you need a full-time COO. Recruitment will take 4–6 months. In the meantime, a fractional COO builds the systems and ships the quick wins so the incoming full-time hire walks into a working operation, not a fire to fight. The fractional then hands over to the new permanent hire.
Pattern 2: Wind-down to advisory. Your interim COO is leaving in two months. You don’t yet need to replace them full-time but you still need senior backup. A fractional engagement (1 day a week) or a Strategic Adviser retainer (monthly) carries the operational thinking forward at a fraction of the cost. We do this regularly. See the Strategic Adviser page.
The honest comparison on cost
A fractional COO at £6,000/month is £72,000/year for 1–2 days a week.
An interim COO at £20,000/month is £240,000/year for 5 days a week.
A full-time COO at £160K base plus 1% equity is roughly £200,000/year all-in for 5 days a week.
If the work is full-time-shaped, the interim is the right comparison and full-time will almost always be cheaper if you can recruit fast enough. If the work is part-time-shaped, fractional is the only sensible choice (interim at part-time hours doesn’t really exist as a market).
For the full framework on full-time vs fractional, read Fractional COO vs Full-Time COO.
How The Edwards Practice fits
We’re a fractional COO practice. We don’t take interim seats, because the time commitment and the day-to-day externally-facing nature isn’t what we’re built for. If you need an interim COO, we’ll happily refer you to people who do that well. If you need a fractional engagement or a Strategic Adviser retainer, you’re in the right place.
- Fractional COO Retainer. From £4,000/month, 3-month minimum.
- Strategic Adviser Retainer. From £1,500/month, 6-month minimum.
- The Ops Audit. One-off, from £5,000. The right starting point if you’re unsure which engagement model fits.
Also worth reading
- What Is a Fractional COO?
- Fractional COO vs Full-Time COO
- How Much Does a Fractional COO Cost in the UK?
- When to Hire a COO: The Series A Operations Checklist
If you’re still unsure which model fits, book a 30-minute discovery call. We’ll work it out together, and tell you honestly if neither of our services is the right answer.