People who search “part-time CMO” and people who search “fractional CMO” are buying the same thing and thinking about it differently. Part-time framing starts with hours and works toward outcomes. Fractional framing starts with outcomes and works back to hours.
The second is more useful, and we'll get there. But the hours question is fair and mostly gets dodged, so here's a straight answer.
What fits in ten hours a week
Roughly forty hours a month. Here's where they go in a well-run light-touch engagement:
- Weekly CEO or founder sync, about 4 hours a month
- Reviewing what the team and agencies produced, about 6 hours
- Numbers, attribution, and the weekly written report, about 8 hours
- Deep work on strategy, positioning, planning, about 12 hours
- Team coaching and one-to-ones, about 6 hours
- Everything unscheduled, about 4 hours
What this buys: your marketing has a direction and someone senior holding it. Campaigns get reviewed by someone who has seen this go wrong before. Your team gets unblocked. The agency gets held to a strategy rather than a deliverables list. Budget decisions get made on evidence. You get an honest weekly read on what's working.
What it doesn't buy: anyone doing the work. Ten hours is direction only. If your team can't execute without close supervision, ten hours produces a well-directed team that still doesn't ship, which is a frustrating place to spend six months.
What fits in fifteen
Everything above, plus roughly twenty hours a month of hands-on ownership. Enough for the CMO to personally run one channel, or build one system properly, or manage a meaningful agency relationship in detail.
Fifteen is the most common shape for a reason. It's the point where the person can both set the direction and personally prove that it works in at least one place, which is usually what an unconvinced sales team or a skeptical board needs to see.
The choice at fifteen hours is what the extra five go into. Demand generation, usually, or content, or ABM. Pick one. Spreading five hours across three channels gives you three channels with a bit of senior attention and none of them working.
What fits in twenty or more
This is a build from zero. No marketing function, no positioning, no clarity on who you sell to. The CMO is designing the function, hiring into it, selecting the stack, and executing until the hires land.
At twenty-plus hours you should expect the engagement to taper. If you're still at twenty hours in month twelve, either the scope kept growing or nothing was handed over. Both are worth naming out loud.
What doesn't fit in any of them
This is the section that should shape your decision.
Managing a team larger than about five people. Past that, one-to-ones alone consume the fractional hours. You need a full-time manager, possibly with fractional strategic support above them.
Being in every meeting. If your culture requires the marketing leader in every commercial conversation, a part-time arrangement will feel permanently absent regardless of the hours.
Crisis management. A PR problem or a major competitive threat needs sustained attention for weeks. A part-time arrangement can handle one crisis. It cannot handle a business that generates one monthly.
Running multiple channels personally. One channel, properly, is realistic. Three is a fantasy that ends with all three underperforming.
Rebuilding a broken sales and marketing relationship. This takes relentless presence over months. It's one of the few marketing problems where physical hours genuinely matter, because the fix is trust and trust is built by being there when things go wrong.
Hours track how much execution the CMO owns personally. Accountability is identical across all three.
Why hours are the wrong unit anyway
Here's the argument for switching frames.
In a week where a fractional CMO kills a channel that was burning budget on leads sales won't call, and rebriefs an agency that had drifted for a month, the value of those two decisions has nothing to do with how long they took. They took an hour combined. They were worth more than everything else that week.
Senior marketing work is lumpy like that. A handful of decisions carry most of the value, and the rest of the hours exist to make sure those decisions get made on good information rather than on instinct. Buying by the hour prices the wrong thing.
The better question is what outcome you need by when, and what it takes to get there. Sometimes that's ten hours. Sometimes it's a full-time hire and the fractional route is a false economy. A provider who asks about outcomes before quoting hours is doing it in the right order.
Structuring the hours so they survive contact with your week
Whatever number you land on, protect the shape of it:
- A fixed weekly leadership slot that doesn't move
- At least one uninterrupted deep work block, because it's the first thing to get eaten
- Defined async availability rather than open-ended Slack presence
- A monthly check that the actual split matches the agreed one
Unstructured part-time is where these arrangements go wrong. Ten scattered hours of interruption produce coordination. Ten structured hours produce decisions. Same invoice, completely different outcome.
For a worked example of how the hours land across a real week, we've written one out in detail.