SEO vs Paid Media: Which Delivers Better ROI?

Let's start with the uncomfortable truth: this isn't an either/or decision. The best-performing companies use both channels strategically. The real question is:

• Where should you start?
• How should you allocate budget?
• When does each channel make sense?

SEO and paid media serve different purposes in your growth engine. Paid provides immediate demand. SEO builds compounding, sustainable traffic. The right mix depends on your stage, runway, and competitive landscape.

That said, let's break down the numbers honestly.

Paid media costs

Paid acquisition costs are straightforward but often underestimated:

• Media spend: £5,000-50,000+/month depending on scale
• Management fees: 10-20% of spend or £1,500-5,000/month retainer
• Creative production: £1,000-5,000/month for ads, landing pages
• Average B2B CPC: £3-15 on Google, £1-5 on Meta
• Typical B2B CPL: £50-200 for qualified leads

SEO costs

SEO costs are less linear but more predictable once established:

• Monthly retainer: £3,000-10,000/month for comprehensive SEO
• Content production: Often included or £500-2,000 per piece
• Link building: £1,000-5,000/month for quality acquisition
• Technical SEO: One-time audits £2,000-5,000 + ongoing
• CPL at scale: £10-50 for organic leads (once ranking)

The key difference: paid media costs scale linearly with volume. SEO costs stay relatively flat while traffic compounds.

This is where most businesses get frustrated — and where honest expectations matter most.

Paid media timeline

• Week 1: Campaigns live, traffic flowing
• Weeks 2-4: Initial optimisation, learning phase
• Months 2-3: Hitting target CAC, scaling what works
• Ongoing: Continuous testing, creative refresh, audience expansion

SEO timeline

• Months 1-2: Technical fixes, content strategy, initial content
• Months 3-4: Rankings start moving, early traffic gains
• Months 5-6: Meaningful organic traffic, first conversions
• Months 7-12: Compounding growth, authority building
• Year 2+: Dominant positions, sustainable low-CAC traffic

If you need leads next month, SEO alone won't save you. If you want sustainable growth over 2-5 years, SEO delivers unmatched ROI.

Here's where the math gets interesting. Let's model a £10,000/month marketing budget over 24 months:

Scenario A: 100% Paid Media

• Total spend: £240,000
• At £100 CPL: 2,400 leads
• At 5% close rate: 120 customers
• CAC: £2,000 per customer
• Month 25 reality: Stop spending, traffic stops

Scenario B: 100% SEO

• Total spend: £240,000
• Months 1-6: Minimal leads (building foundations)
• Months 7-24: Compounding traffic, ~3,000 leads
• At 5% close rate: 150 customers
• Blended CAC: £1,600 per customer
• Month 25 reality: Traffic continues without spend

Scenario C: 60% Paid / 40% SEO (Our recommendation)

• Paid delivers immediate pipeline while SEO builds
• Gradually shift budget as organic traffic grows
• Year 2: 40% paid / 60% SEO
• Combined leads: ~3,200
• Blended CAC: £1,500 per customer
• Month 25 reality: Reduced paid spend, organic carrying majority

Prioritise Paid Media when:

• You need leads in the next 30-90 days
• Testing new markets, offers, or messaging
• Launching a new product or service
• Short runway and need immediate revenue
• Competitive keywords have 12+ month ranking timelines

Prioritise SEO when:

• You have 6-12 months of runway to invest
• Your market has consistent search demand
• Content and thought leadership align with your brand
• You want to reduce long-term CAC
• Competitors are winning organic and you're not

Run both when:

• You have budget for sustainable investment in both
• You want short-term pipeline AND long-term growth
• You're in a competitive market where both matter
• You want to use paid data to inform SEO content strategy

We see these patterns consistently lead to poor ROI:

• Killing SEO after 3 months — SEO compounds. Stopping before month 6 wastes everything you've invested.
• Scaling paid without conversion optimisation — More traffic to a broken funnel just burns money faster.
• Treating channels as silos — Paid data informs SEO. SEO content supports remarketing. They work together.
• Chasing vanity metrics — Traffic and impressions don't matter. Revenue and CAC matter.
• Not tracking attribution properly — Multi-touch attribution is messy but essential. First-click and last-click both lie.

The businesses that win understand that marketing is portfolio management, not a single bet.

Our SEO & Organic Growth services are built around this exact framework, designed for businesses that need predictable growth.

See how we applied this approach in our client case studies.