There’s no universally correct answer here. The right model depends on your budget, your growth stage, the complexity of your site, and how central organic search is to your business. An in-house hire makes perfect sense for some companies. Outsourcing to an agency is the smarter move for others. And for most mid-market businesses, some combination of the two ends up working best.
What matters is making that decision with clear numbers and honest trade-offs rather than gut feeling. This guide breaks down the real costs, capabilities, and risks of each model so you can figure out what actually fits.
What Does Each Model Really Cost?
Cost is usually the first question. It shouldn’t be the only one, but it’s the one that gets answered with the least accuracy. Most comparisons you’ll find online use US salary data, which isn’t much help if you’re hiring in Manchester or Bristol. Here’s what the numbers actually look like in the UK.
In-house SEO manager
A mid-level SEO manager in the UK commands a salary of around £35,000 to £55,000. But salary is just the start. Add employer National Insurance contributions, pension, annual leave cover, and the tools they’ll need to do the job properly (Ahrefs or Semrush alone runs £1,200 to £3,000 a year), plus ongoing training and conference budgets. Fully loaded, you’re looking at £45,000 to £75,000 per year. That’s £3,750 to £6,250 a month before they’ve produced a single deliverable.
Agency retainer
A competent mid-market SEO agency in the UK typically charges £1,500 to £5,000 per month on retainer. For a fuller breakdown of what those price bands get you, we’ve covered this in detail in our guide to how much SEO costs in the UK.
Freelancer
Freelance SEO consultants in the UK charge anywhere from £50 to £150 per hour, or £1,000 to £4,000 per month on a retainer basis. Quality varies enormously, and IR35 legislation means you need to think carefully about how the engagement is structured if they’re working regularly and exclusively for you. HMRC doesn’t care what you call it; if it looks like employment, they’ll treat it that way.
Side-by-side comparison
| In-House SEO Manager | Agency Retainer | Freelancer | |
|---|---|---|---|
| Monthly cost | £3,750 – £6,250 | £1,500 – £5,000 | £1,000 – £4,000 |
| Annual cost | £45,000 – £75,000 | £18,000 – £60,000 | £12,000 – £48,000 |
| Breadth of expertise | Single person | Full team | Single person |
| Business knowledge | Deep (over time) | Moderate | Moderate |
| Tool costs | Included in annual figure | Included | Usually included |
| Commitment | Employment contract | Flexible (monthly/quarterly) | Flexible |
| Recruitment risk | High | Low | Moderate |
The numbers speak for themselves, but cost alone doesn’t tell you which model delivers more. A £4,000/month agency retainer that drives measurable organic growth is better value than a £55,000/year hire who’s out of their depth. And a brilliant in-house SEO who knows your product inside out will outperform any external provider who’s spread across 20 accounts. Context matters.
What Does an In-House SEO Give You?
The case for hiring internally is straightforward. Nobody will understand your business, your customers, and your internal politics the way someone who sits in the office every day does.
Deep product knowledge. An in-house SEO lives and breathes your brand. They sit in on product meetings, hear customer feedback first-hand, and understand the commercial priorities that shift quarter to quarter. That context is hard to replicate externally.
Speed of communication. Need a page updated before a product launch? No tickets, no briefing documents, no waiting for the next monthly call. They’re already there.
Dedicated focus. Your site is their only site. Every hour of their working day goes toward your organic performance. No shared attention, no competing client priorities.
Cultural alignment. They understand the brand voice, the internal approval processes, and which stakeholders need to sign off on what. That institutional knowledge compounds over time.
But the downsides are real, and they’re the ones that catch people out.
Single point of failure. One person gets ill, hands in their notice, or goes on parental leave, and your entire SEO operation stops. There’s no bench.
Knowledge gaps are inevitable. SEO spans technical SEO, SEO content, link building, local SEO, analytics, and increasingly PPC integration. Finding one person who’s genuinely strong across all of those is difficult. Finding one you can afford is even harder.
Recruitment risk. A bad hire costs more than their salary. You’re looking at 6 to 9 months of recruitment costs, onboarding time, and lost momentum before you even start again. The SEO job market in the UK is competitive, and the gap between a competent SEO and someone who can talk the talk in an interview is wider than you’d think.
Tool costs add up. Enterprise SEO tools, crawlers, rank trackers, content optimisation platforms. These subscriptions stack quickly, and they’re essential, not optional.
What Does an Agency Give You?
The core advantage of an agency is breadth. Instead of one person trying to cover everything, you get a team with specialists across strategy, content, technical, and link building. That’s not a luxury; for most businesses, it’s the practical reality of what SEO actually requires.
No recruitment risk. If a strategist leaves the agency, that’s the agency’s problem to solve, not yours. You still get continuity of service.
Built-in tools and processes. A decent agency has already invested in the tooling, the reporting infrastructure, and the workflows. You don’t need to build that from scratch.
Scalability. Need to ramp up content production for a seasonal push? Need technical resource for a site migration? An agency can flex. A single hire can’t.
Cross-client insight. Agencies see patterns across industries and verticals that an in-house team of one simply can’t. What’s working in e-commerce, what Google’s latest update actually affected, which link building tactics are still delivering. That breadth of exposure has real value.
The trade-offs are equally honest.
Less embedded in your business. However good the onboarding, an agency will never know your product as intimately as someone internal. The best agencies work hard to close that gap, but it exists.
Shared attention. Your account is one of many. The quality of your experience depends entirely on the agency’s account management, their capacity planning, and whether they’ve oversold their team. This is where quality varies wildly across the market. Some agencies deliver exceptional, senior-led work. Others assign your account to a junior who’s learning on the job while you’re paying premium rates.
Transparency varies. Some agencies operate as genuine partners with full visibility into what they’re doing and why. Others treat their process as a black box and hand you a PDF report once a month. The difference matters enormously. If you’re considering an agency, we’ve written a separate guide on how to choose the right one.
The Hybrid Model: Why Most Mid-Market Businesses End Up Here
Here’s what we see most often with businesses turning over £2m to £30m. They have an internal marketing manager or head of digital who handles the day-to-day coordination, brand messaging, and internal stakeholder management. And they partner with an agency for specialist execution and strategic direction.
This works because it plays to each side’s strengths. The internal person owns the business context. The agency brings the technical depth, content production capacity, and strategic experience. Neither side is trying to do something they’re not set up for.
In practice, it usually looks like this:
Internal marketing lead handles content briefs, approvals, and internal comms
Agency delivers the SEO strategy, technical audits, content production, and link acquisition
Monthly or fortnightly calls to align on priorities
Shared access to reporting dashboards and project management tools
The hybrid model also reduces risk. If the internal person leaves, the agency provides continuity. If you need to change agency, the internal lead retains the institutional knowledge and strategic context.
It’s not the cheapest option on paper. But it’s often the most effective one per pound spent.
When Does Each Model Make Sense?
Rather than a generic “it depends,” here’s a practical framework.
Go in-house when:
Organic search is central to your revenue model (e.g., you’re an online publisher, a marketplace, or a large e-commerce site with thousands of product pages)
You have enough work volume to keep a full-time person busy every day
Your budget stretches to senior talent, not just a junior who’ll need managing
You can support them with tools, training, and ideally a small team around them
Go agency when:
You need breadth of expertise that one hire can’t cover
Your budget doesn’t stretch to a senior in-house SEO (remember: fully loaded, that’s £45k+ a year)
You want results without a 3 to 6 month recruitment and onboarding cycle
SEO is important to your business but isn’t your only marketing priority
You’re going through a specific project (site migration, international expansion, technical overhaul) that needs specialist resource
Go hybrid when:
You have a generalist marketer or small marketing team who needs specialist support
You want strategic direction and specialist execution without building a full in-house function
You’re scaling and need the flexibility to increase or decrease SEO investment without hiring or firing
How Quickly Can Each Model Deliver Results?
This catches people off guard. An agency with established processes, tooling, and experience in your sector can start delivering meaningful work from month one. The audit happens in weeks, not months. Strategy development runs in parallel with quick wins. Content production and technical fixes begin almost immediately.
An in-house hire? You’re looking at 1 to 3 months to recruit (if you’re lucky and don’t have a notice period to wait out), another month or two for onboarding and getting up to speed with your tech stack, content management system, and internal processes. Then they need to develop the strategy. Realistically, you’re 3 to 6 months in before meaningful execution begins.
That’s not a criticism of in-house SEOs. It’s just the reality of hiring. And in a channel where compound growth matters, those lost months have a real cost.
The Cost of Getting It Wrong
A bad agency engagement costs you the retainer fees and some lost months. Painful, but recoverable. You cancel the contract, find a better provider, and move on. If they haven’t done anything harmful (dodgy link building, poor technical changes), the damage is contained.
A bad hire is a different kind of problem. Recruitment fees (typically 15 to 25% of salary for a specialist role), 3 to 6 months of salary before you realise it isn’t working, the HR process of managing them out, then starting the recruitment cycle again. You could easily burn £30,000 to £50,000 and lose 9 to 12 months of progress. For a mid-market business, that’s not just a line item. It’s a competitive setback.
Neither outcome is inevitable, of course. Plenty of businesses hire brilliant in-house SEOs, and plenty of agency partnerships deliver outstanding results. The point is to understand the downside risk of each model so you can plan accordingly.
Making the Decision
The question isn’t whether in-house SEO is better than agency SEO. It’s which model gives your specific business the best chance of sustained organic growth, given your budget, your team, and your priorities right now.
If you’re weighing up the options and want an honest conversation about what would actually work for you, that’s what we’re here for. Gorilla Marketing works as an extension of your team, with senior strategists on every account, transparent reporting, and no long-term lock-ins. Whether you need a full-service agency partnership or specialist support alongside your internal team, we’ll tell you straight which model makes sense for your situation, even if the answer is “hire someone in-house.”
