Founders comparing a fractional AI/CTO retainer to a full-time hire often start with the wrong question: "what's cheaper?" The honest answer depends on the engagement, but the more useful question is: "what's the right shape of leverage for this stage of the business?"
The math, plainly:
- A senior AI/engineering exec hire is $400K–$600K all-in (salary, equity, benefits, recruiter fees), and the search takes 3–6 months.
- A fractional retainer is $60K–$180K/year, starts in two weeks, and has no recruiter fees.
- The full-time hire owns the org full-time. The fractional engagement is shaped to specific outcomes: AI strategy, governance, hiring support, architecture review, embedded leadership presence at exec rhythm.
The fractional engagement makes sense when:
- You're pre-CTO and not yet ready to commit to the wrong full-time hire.
- You're between CTOs and don't want to lose six months.
- You have a CTO who needs an AI specialist partner, not a replacement.
- The board / PE is staging in AI leadership ahead of a full-time placement.
It does not make sense when:
- You need someone full-time on the org. (You probably do, eventually.)
- The work is hands-on coding more than 50% of the time. (That's a different engagement — closer to a Build.)
A good fractional engagement is shaped to make itself unnecessary. The end state is either a full-time CTO transition, where the fractional has done the search and the onboarding plan, or a continued partnership focused on the AI surface specifically.
If you're staring at this fork right now, book a call — most of these conversations are short and clarifying.