Google Ads and Facebook Ads are the two dominant paid media platforms, and almost every business that runs digital advertising will eventually use both. But they work in fundamentally different ways, reach users at different stages of the buying journey, and suit different types of businesses and campaigns. Choosing the wrong platform — or allocating budget incorrectly between them — is one of the most common and costly mistakes in paid media.
This guide breaks down exactly how each platform works, where each one wins, how costs compare, and how to decide where to start.
The Fundamental Difference: Intent vs Interest
The most important thing to understand about Google Ads and Facebook Ads is the psychological state of the person seeing your ad.
Google Ads — specifically Search campaigns — captures existing demand. Someone types “accountant for small business London” into Google. They have a problem, they know they need a solution, and they are actively looking for it. Your Search ad appears at the moment of maximum purchase intent. You are not interrupting anyone — you are responding to a request.
Facebook Ads interrupts people who are not actively looking for your product. Someone is scrolling through their feed, seeing content from friends and family, and your ad appears in between. They may or may not be interested. They were not searching for you — you found them based on demographic and interest data. This is demand generation, not demand capture.
This distinction determines almost everything else about how the two platforms perform and when to use each.
How Google Ads Works
Google Ads runs across several channel types, each with different mechanics:
Search campaigns show text ads on Google’s search results page when users search for specific keywords. You bid on keywords, and Google matches your ads to relevant searches. Clicks cost more than on most other platforms, but the conversion rates are typically much higher because the user is already looking for what you offer.
Display campaigns show image and text ads across millions of websites in Google’s Display Network. These reach users while they are browsing other sites, not while they are searching. Display is better for awareness and remarketing than for direct conversion.
Shopping campaigns show product listings (image, price, store name) directly in search results for ecommerce businesses. Shopping ads typically have higher click-through rates than text ads for product searches because they show the product visually before the click.
Performance Max campaigns run across all Google channels simultaneously using AI to optimise creative and bidding. They sit alongside Search campaigns rather than replacing them, and work best for accounts with strong conversion data.
YouTube campaigns show video ads before and during YouTube content. YouTube sits in a middle ground — users are not actively searching (usually), but the targeting and intent signals available are stronger than on Facebook.
How Facebook and Instagram Ads Work
Facebook Ads (managed through Meta Ads Manager, which controls both Facebook and Instagram) targets users based on who they are rather than what they are searching for. The targeting options include:
Demographic targeting: Age, gender, location, language, job title, education, relationship status.
Interest targeting: Pages people follow, content they engage with, categories of interest Meta has inferred from behaviour.
Behavioural targeting: Purchase behaviour, device usage, travel patterns, and other inferred signals.
Custom audiences: Upload your own customer list, retarget website visitors, or target people who have engaged with your content or app.
Lookalike audiences: Meta finds users who share characteristics with your existing customers. Lookalike audiences are one of the most powerful tools in the Facebook Ads toolbox when built from a clean, high-quality source audience.
Facebook and Instagram ads appear in feeds, Stories, Reels, the right column on desktop, Messenger, and across Meta’s Audience Network. The creative formats are more visual than Google — images, videos, carousels, and collection ads are the primary formats.
Cost Comparison: CPC, CPM, and What Actually Matters
Facebook Ads typically has a lower cost per click and cost per thousand impressions (CPM) than Google Search. Average CPCs on Facebook are often in the range of £0.50 to £2.00, while Google Search CPCs for competitive keywords can easily reach £5 to £50 or more.
But cheaper clicks do not mean better results.
Google Search clicks come from people actively looking for your product. Even at £10 per click, if 10 percent of those users convert, your cost per acquisition might be £100 — which could be highly profitable. Facebook clicks at £0.80 each might convert at 1 percent, giving you a cost per acquisition of £80 from a colder audience that takes longer to close.
The right comparison metric is cost per qualified lead or customer, not cost per click. Calculate this separately for each platform, including the lifetime value of customers acquired through each channel. In many B2B and high-value service industries, Google Ads generates higher-quality leads that close faster. In ecommerce and direct-to-consumer, Facebook’s visual formats and interest targeting can drive lower acquisition costs for impulse or discovery purchases.
When Google Ads Wins
Google Search is typically the stronger choice when:
- Your product or service has clear search demand — people are actively typing queries related to what you sell.
- Your buying cycle is short and high-intent — users who find you through search tend to be ready to act.
- You are selling B2B services, professional services, or anything where the purchase decision is rational rather than impulse-driven.
- Your audience is defined by what they need (a search query) rather than who they are (demographics and interests).
- You want measurable, direct-response results with clear attribution.
If someone is searching for “emergency plumber London” or “Google Ads management agency” or “accountant for freelancers,” Google Search is the only place to reach them at that exact moment of intent. No amount of Facebook targeting can replicate that.
When Facebook Ads Wins
Facebook and Instagram Ads are typically the stronger choice when:
- Your product is visual or discovery-based — fashion, food, home décor, beauty, consumer gadgets.
- You are launching a new product or category that people are not yet searching for. You cannot capture demand that does not exist yet — you have to create it.
- Your audience is defined by who they are (age, interests, life stage) rather than what they are searching for.
- You are targeting specific demographics or communities with precision — niche audiences, specific age groups, users with particular life events.
- You want to build brand awareness and run upper-funnel campaigns that nurture audiences over time.
- You are running retargeting campaigns for people who have already visited your site or engaged with your brand.
Facebook’s creative flexibility is also a significant advantage. Video, carousel, and collection ad formats allow you to tell stories and showcase products in ways that Google’s text-based Search ads cannot match.
Running Both Platforms Together
For most established businesses, the question is not Google Ads or Facebook Ads — it is how to allocate budget across both. The two platforms serve different purposes in the funnel and complement each other well.
A common and effective approach is to use Facebook Ads at the top of the funnel to generate awareness and interest — particularly for audiences who do not yet know your brand exists — and then use Google Search to capture the intent-driven searches that follow. Someone sees your Facebook ad today, thinks about it for a few days, then searches for you on Google next week. That conversion gets attributed to Google, but Facebook played a role in creating the demand.
Remarketing is where the two platforms integrate most directly. Retargeting your Google Ads website visitors on Facebook and Instagram, or retargeting your Facebook video viewers on Google Display, creates multi-touchpoint campaigns that tend to significantly outperform either platform alone. This cross-platform remarketing strategy is particularly effective for considered purchases with longer decision cycles.
Where to Start: A Decision Framework
If you are starting from scratch with a limited budget, here is a simple decision framework:
Start with Google Search if: there is clear search volume for your product or service (check Google Keyword Planner), your average order value or LTV justifies a higher CPC, and you need direct, measurable results quickly.
Start with Facebook Ads if: you have a visual product that benefits from creative showcasing, you are targeting a specific demographic or interest group that is hard to reach via search, or you want to build awareness before capturing intent.
Run both if: you have tested one platform and are generating positive ROI, you have a clear upper-funnel and lower-funnel strategy, and your budget allows meaningful spend on each (typically at least £1,500 to £2,000 per month per platform to generate sufficient data).
Frequently Asked Questions
Should I run Google Ads or Facebook Ads first?
If your audience is actively searching for your product or service, start with Google Ads. Search campaigns capture existing demand, which means faster feedback and a clearer path to ROI. If your product needs to be discovered (new category, impulse purchase, or visual product), start with Facebook and Instagram Ads. Many businesses eventually run both, but starting with the platform that matches your buying cycle gives you the strongest foundation.
Which platform is cheaper, Google Ads or Facebook Ads?
Facebook Ads generally has lower cost per click and cost per thousand impressions. However, cheaper clicks do not always mean better results. Google Ads clicks tend to have higher intent, so the conversion rate is often higher. The real comparison should be cost per acquisition or cost per qualified lead, not cost per click. In many B2B and high-value service industries, Google Ads delivers a lower cost per acquisition despite higher CPCs, because the leads are warmer and close faster.
Can I run Google Ads and Facebook Ads at the same time?
Yes, and for most businesses with sufficient budget, running both is the strongest strategy. Use Google Search to capture high-intent users who are actively looking for your product, and use Facebook and Instagram to build awareness, reach cold audiences, and retarget warm audiences who did not convert. The two platforms complement each other at different stages of the buying funnel. Budget allocation depends on your margins and where each platform delivers the better cost per acquisition for your specific business.
Which platform is better for B2B lead generation?
Google Ads typically performs better for B2B lead generation, especially for services with clear search demand. Business buyers who need a specific solution — an accountant, a software tool, a logistics provider — search for it. LinkedIn Ads is also worth considering for B2B, particularly for targeting by job title, seniority, or company size. Facebook can work for B2B if your audience has identifiable interests and you are running longer-nurture campaigns, but it is rarely the primary B2B lead generation channel.
How do I track which platform is driving more revenue?
Use proper conversion tracking on both platforms — Google Ads conversion tracking with Google Tag Manager, and Meta Pixel with the Conversions API for Facebook. Implement consistent UTM parameters across all paid campaigns so your CRM and GA4 can attribute revenue to each channel. For full-funnel attribution, track leads all the way through to closed revenue in your CRM, then compare the quality and close rate of leads from each source — not just the volume.
