Fractional CTO or interim CTO: two jobs that share a title
One is a day or two a week for as long as it's useful. The other is a full-time seat with an end date. Which you need depends on whether the chair is empty or the decisions are.
Search for help running your technology and you’ll meet six names for what looks like one job: fractional CTO, interim CTO, part-time CTO, virtual CTO, outsourced CTO, CTO as a service. Five of them are the same thing. One is a different job, and hiring it by mistake is expensive.
Five names, one arrangement
Fractional, part-time, virtual, outsourced and “as a service” all describe the same deal. A senior person owns your technology decisions for a slice of the week, on a monthly fee, and either side can end it with notice. The label tells you who wrote the website and nothing about the work.
So don’t compare a “virtual CTO” with a “fractional CTO” as though they were products. Compare the people: what they’ve run, what they’ve built, and whether they’ve ever answered for a budget of their own.
Interim is the odd one out
An interim CTO takes the seat full-time, for a fixed period measured in months. They manage the team day to day, sit in the leadership meeting every week, and hold the line until a permanent hire arrives or an event completes.
The cases that call for one are easy to recognise. Your CTO has resigned and the team has nobody to report to. You’re mid-sale and the buyer wants a named technical lead in place through completion. A large programme is in flight and can’t pause while you recruit.
In each of those the chair is empty and people are waiting on whoever sits in it. A day a week doesn’t fill a chair.
How to tell which you need
One question does most of the work. Are decisions missing, or is a manager missing?
Say the team is functioning and what’s absent is direction: what to build next, which architecture, whether the agency’s quote is sane, what to tell the board. Decisions are missing, and you need a fractional CTO. A day or two a week is enough, because a good decision takes the right person an afternoon and then takes other people a week to carry out.
Now say eight engineers have no line manager, stand-ups have stopped and releases are slipping because nobody is chasing them. A manager is missing. You need an interim, and a fractional arrangement will disappoint both of you.
| Fractional CTO | Interim CTO | |
|---|---|---|
| Time | A day or two a week | Full-time |
| Length | Open-ended, ends on notice | Fixed, ends on a date or an event |
| Fills | A gap in decisions | An empty seat |
| Manages the team daily | No | Yes |
| Right when | The team works and the direction doesn’t | The team has nobody to answer to |
Where people go wrong
The mistake I see most runs one way. A founder loses a CTO, feels the hole, and hires a fractional one because the monthly figure is smaller. Three months later the team is still drifting, because what it lacked was somebody present on a Tuesday morning.
The reverse happens too. A business with four developers and no technical leadership hires a full-time interim at a full-time price, and finds there were about two days of CTO work in the week. The other three fill up with jobs a good senior developer should have been doing.
Price follows time. If you’re weighing the two on cost, read what a fractional CTO costs in the UK first, then ask how many days of senior attention your situation can use.
What I do, and what I don’t
I work fractionally. A retainer with me is a day or two a week, and I stay reachable for a decision in between. I don’t take interim roles, for a plain reason: I’m the CEO of a business of my own and I manage its technical team, so a full-time seat somewhere else is a promise I couldn’t keep.
The same fact is why the fractional version works. Every week I make technology decisions with my own money behind them, and then I live with what they cost. When I tell you an architecture is more than your business needs, I’ve paid for that lesson myself.
If you’ve read this far and you need an interim, hire one. Ask what happened to the last team they handed back, and ring the person they handed it to.
If what’s missing is decisions, that’s the work I do.