The real comparison is not cost
On paper an in-house marketer at £45,000 and an agency at £3,500 a month cost roughly the same. The difference is what you get for the money and how quickly you get it.
What one hire gives you
One person, one skill set. Most email marketers are strong at either copy, design, data or platform mechanics — rarely all four. They also need managing, tooling, training and cover for holidays and sickness. Time from job ad to productive output is typically three to five months.
What outsourcing gives you
A team: strategist, copywriter, designer, developer and analyst, each doing the part they are best at. Onboarding is usually two to four weeks. You also inherit patterns from other accounts, which matters most in deliverability and flow design where mistakes are expensive.
Where in-house genuinely wins
- Deep product complexity. If understanding the product takes months, an employee's context is worth more than agency speed.
- Very high send volume with a stable programme. Once the strategy is settled and the work is execution, in-house is cheaper per email.
- Regulated industries with heavy internal sign-off, where being in the building removes weeks of friction.
- Email as the core business, for example a publisher or newsletter business where the product is the email.
Where outsourcing wins
- You need results this quarter, not after a hiring cycle.
- The channel is underperforming and you do not know why — diagnosis is a specialist skill.
- You need several skills at once: deliverability repair plus a template rebuild plus flow strategy.
- Volume is seasonal and a full-time salary is dead weight for half the year.
The hybrid most mature teams end up with
An in-house marketing manager who owns the calendar, the brand and the stakeholders, with an agency handling strategy, build and technical work. This is usually the best value once revenue passes a few million: you keep the context and buy the specialisms.
A simple decision test
Ask what would break first if email doubled in importance tomorrow. If the answer is capacity, hire. If the answer is capability, outsource. If it is both, hybrid.
Read the full outsourced email marketing service breakdown, or check the UK cost ranges for both routes.