When to Hire a Fractional CTO vs a Full-Time CTO
The Wrong Question
Most founders frame this as a cost question: "Can we afford a full-time CTO?" The right question is: "What kind of technical leadership do we actually need right now?"
A $300k/year full-time CTO who's wrong for the stage is more expensive than a $9k/month fractional who's right for it.
The Stage Framework
Pre-Product-Market Fit (Seed to Series A)
What you need: Someone to make fast architectural decisions, ship the MVP, and not over-engineer.
Best fit: Fractional CTO
At this stage, you need 10-15 hours/week of senior technical judgment, not 50 hours of management. A fractional CTO can:
- Set the initial architecture
- Vet and hire the first 2-3 engineers
- Establish coding standards and deployment practices
- Make build-vs-buy decisions
- Keep the technical roadmap aligned with fundraising milestones
Why not full-time: You don't have enough technical decisions to fill 40 hours/week. A full-time CTO at this stage either gets bored and over-engineers, or does IC work that a senior engineer could do for less.
Growth Stage (Series A to B)
What you need: Technical leadership that scales the team and systems simultaneously.
Best fit: It depends.
This is the inflection point. Ask these questions:
| Question | If Yes → Full-Time | If No → Fractional |
|---|---|---|
| Engineering team > 8 people? | Need daily management | Fractional can handle |
| Shipping daily? | Need embedded leadership | Weekly check-ins work |
| Complex compliance requirements? | Need dedicated attention | Periodic review works |
| Technical co-founder leaving? | Need continuity | Transition support works |
| Fundraising requires "CTO on team"? | Optics matter | Results matter more |
Scale Stage (Series B+)
What you need: A full-time executive who owns the technical vision, manages a growing org, and sits in the leadership team.
Best fit: Full-Time CTO
At this point, the role is 70% people management and organizational design, 30% technical decisions. That requires full-time presence.
When fractional still works at scale: Specific projects (AI implementation, platform migration, security audit) where you need deep expertise for 3-6 months, not permanently.
The Cost Reality
Let's be honest about the numbers:
| Fractional CTO | Full-Time CTO | |
|---|---|---|
| Monthly cost | $9k-15k | $25k-40k (salary + equity + benefits) |
| Annual cost | $108k-180k | $300k-500k+ |
| Ramp-up time | 1-2 weeks | 1-3 months |
| Exit cost | End of contract | Severance, transition, morale impact |
| Equity dilution | None | 1-3% typical |
| Availability | 10-20 hrs/week | 40-60 hrs/week |
But cost isn't the full picture. The real comparison is value per dollar:
- A fractional CTO who ships a critical system in 90 days at $45k total
- vs. A full-time CTO who spends 90 days "getting up to speed" at $75k+ total
What a Good Fractional CTO Actually Does
It's not "part-time CTO." It's concentrated technical leadership:
Week 1-2: Audit
- Map the current architecture and technical debt
- Assess team capabilities and gaps
- Identify the top 3 business-critical technical risks
Ongoing: Leadership
- Set technical direction and priorities
- Run sprint planning and architecture reviews
- Mentor senior engineers toward technical leadership
- Provide the CEO with honest technical assessments
Deliverables: Monthly
- Technical roadmap aligned with business goals
- Risk register with mitigation plans
- Team performance and hiring recommendations
- "State of Engineering" truth report
Red Flags: When Fractional Won't Work
Be honest about when you need full-time:
- Your team needs daily management — if engineers need constant direction, you need someone there every day
- You're in crisis mode — active security breach, system down, regulatory deadline
- The role is mostly people management — 8+ engineers need a dedicated manager
- You need a public-facing technical leader — conferences, press, investor meetings
- Institutional knowledge is critical — complex domain that takes months to learn
The Transition Path
The best fractional engagements have a built-in transition plan:
Month 1-3: Fractional CTO leads
→ Audit, roadmap, quick wins, team assessment
Month 4-6: Fractional CTO + hiring
→ Define the full-time CTO role based on real needs
→ Fractional helps interview and evaluate candidates
Month 7-9: Overlap period
→ Full-time CTO onboards with fractional support
→ Knowledge transfer, relationship handoff
Month 10+: Full-time CTO leads
→ Fractional available for advisory if needed
This is how you get the right full-time CTO — by having a fractional define what "right" actually means for your company.
The Decision
If you're reading this article, you probably need a fractional CTO. Companies that need a full-time CTO already know it — they have 15+ engineers, a complex product, and organizational challenges that require daily presence.
Everyone else? Start fractional. Get the roadmap right. Build the foundation. Then hire full-time when the role is clearly defined and the company is ready for it.