Google Ads vs LinkedIn: The B2B SaaS London Guide

Right then. You're a B2B SaaS founder in London. You've built something you believe in, but now you need customers. And you're staring at the two big beasts of B2B advertising: Google and LinkedIn. Everyone's got an opinion, most of them wrong. They'll tell you it's one or the other. That's nonsense. The real question isn't which platform to use, but when and why to use each one.

Pouring money into either without a clear strategy is like trying to drive from Shoreditch to Richmond at 5pm with no map. You'll spend a lot, get nowhere, and end up incredibly frustrated. I've seen countless London startups burn through their seed round on ads that were doomed from the start. The problem usually isn't the platform, it's the thinking behind the campaign. It's about understanding demand, not just chasing clicks. And frankly, it's about having an offer that doesn't make your ideal customer yawn and close the tab. Before you spend another pound, lets get this sorted.

So, When is Google Ads the Right Move?

Think of Google Ads as a net. It's brilliant at catching people who are already swimming towards you. These are prospects who have a problem, they know they have a problem, and they are actively typing that problem into a search bar. This is called search intent, and it's the most powerful buying signal on the internet. If people are looking for a solution like yours, you absolutely must be there when they search.

I remember working with a B2B SaaS that sold a niche medical job matching platform. Initially, their cost per user was a painful £100. They were trying to convince people they needed a better system. We flipped it. We focused almost entirely on Google Ads, targeting the exact phrases recruiters and medical pros were searching for when they were fed up with their current options. Keywords like "locum doctor platform UK" or "find specialist nurse jobs". They were already looking for a solution. We just had to show them ours was the best. Their CPA dropped from £100 to just £7. That's the power of capturing existing demand.

Your job here isn't to create a need. It's to prove you're the best solution for a need that already exists. This means your focus should be on keywords that show commercial intent.

• Problem/Solution Keywords: "how to automate employee onboarding", "best crm for small business uk"
• Competitor Keywords: "salesforce alternative", "cheaper than hubspot" (be careful here, it can be expensive)
• Category Keywords: "accounting software for agencies", "project management tool"

If your SaaS solves a problem people are aware of, Google Ads is your starting point. You're entering a conversation that's already happening. For a deeper look, our complete guide to Google Ads for B2B SaaS is a good next step. The competition in the capital means you have to be extra sharp, something we cover specifically for local businesses in our London SaaS Google Ads guide.

And When Does LinkedIn Ads Make Sense?

LinkedIn is different. It's not a net; it's a sniper rifle. People aren't on LinkedIn searching for your software. They're networking, reading industry news, or looking for their next job. You're not catching demand here; you're creating it. You're interrupting their day with a message so relevant and targeted they have to pay attention.

This is where LinkedIn's targeting is frankly, terrifyingly good. You can bypass the gatekeepers and put your ad directly in front of the exact people who make the buying decisions. Want to target "Heads of Engineering" at "FinTech companies" with "50-200 employees" located within "the M25"? You can do that. It's a level of precision Google can't touch.

I remember one campaign we ran for a software client. Their ideal customers were CMOs and Heads of Sales in specific B2B sectors. They weren't searching for data enrichment tools because many didn't even know that was a category. Instead, they were feeling the pain of having a rubbish CRM full of outdated contacts. We used LinkedIn to target those exact job titles with ads that spoke to that pain. The result was a stream of qualified leads at about $22 a pop, which for that high-ticket service, was an absolute steal. It worked because the targeting was so precise.

LinkedIn is your best bet when:

• You have a clearly defined, niche ICP (Ideal Customer Profile).
• Your solution is innovative, and people aren't actively searching for it yet.
• Your deal sizes are large, justifying a potentially higher Cost Per Lead.
• You need to reach specific decision-makers within target accounts (Account-Based Marketing).

Don't just think about demographics. Think about the nightmare your ICP is living. The Head of Finance isn't just a job title; she's terrified of a cash flow crisis. Your ad needs to speak to that fear. Getting this right is a whole topic in itself, which is why we've put together a full guide on LinkedIn Ads for B2B SaaS.

How Much Should You Be Paying? The LTV to CAC Calculation Every Founder Must Know

This is where most founders get it wrong. They obsess over a low Cost Per Lead (CPL) without knowing what a lead is actually worth to them. "Is a £50 CPL good?" It's a meaningless question without context. A £50 CPL for a customer worth £200 is a disaster. A £500 CPL for a customer worth £50,000 is a money-printing machine.

You need to know your Lifetime Value (LTV). This number dictates your entire growth strategy. Here's how you work it out, no fluff:

• Average Revenue Per Account (ARPA): How much you make from one customer, per month.
• Gross Margin %: Your profit on that revenue.
• Monthly Churn Rate: The percentage of customers you lose each month.

The formula is: LTV = (ARPA * Gross Margin %) / Monthly Churn Rate

Once you know your LTV, a healthy business model aims for a LTV to Customer Acquisition Cost (CAC) ratio of at least 3:1. This means you can afford to spend up to a third of your LTV to acquire a customer. This single calculation changes everything. It stops you from being scared of spending money and allows you to invest intelligently in growth. To make it easier, I've built a little calculator for you.

Which Platform First? A Decision Framework for London Founders

Okay, so you understand the theory. But you've got a limited budget and you need to make a choice. Where do you put your first £5,000? Let's make this simple. The right platform depends entirely on your product, your market, and how aware they are of the problem you solve. A direct comparison can be useful, but a simple flowchart is often better.

The Secret Weapon: Your Offer (Hint: It's Not "Request a Demo")

Here's the bit everyone gets wrong. You can have the most perfectly targeted campaign in the world, but if your offer stinks, you'll fail. The "Request a Demo" button is the laziest, most arrogant call to action in B2B marketing. It screams, "Give me an hour of your valuable time so my sales rep can pitch to you". It's high friction and low value for the prospect.

You need to flip this on its head. Your offer's only job is to provide undeniable value, for free, right now. You need to give them an "aha!" moment that makes them sell themselves on your product.

• The Gold Standard (SaaS): A completely free trial, no credit card required. Or a generous freemium plan. Let them use the actual product. Let them solve a small part of their problem. This generates Product Qualified Leads (PQLs) who are already halfway to buying. One of our SaaS clients selling an events app saw over 45,000 signups at under £2 each by focusing purely on getting people into the app, not onto a sales call.
• The Non-SaaS Equivalent: Bottle your expertise into a tool or asset. An agency could offer a free, automated website audit. A data platform could offer a free 'Data Health Check'. For us, it's a free, no-obligation strategy session where we actually look at people's ad accounts and give them real advice. You have to give value to get value.

An irresistible offer makes your entire paid acquisition strategy easier. Your ads get more clicks, your landing pages convert better, and your CAC plummets. Don't even think about scaling your ad spend until you've perfected your offer. This principle is a cornerstone of our entire paid acquisition philosophy for founders.

This all might feel like a lot to take on, especially when you're also trying to build a product and run a company. Getting paid advertising right is a specialism, and in a market as competitive as London, the margin for error is slim. There's a big difference between just 'running ads' and building a predictable, scalable customer acquisition engine. For a local perspective on this, it's worth understanding how to find the right partner with our guide on choosing a B2B ad agency in London.

This is my main advice for you:

Here’s a table summarising the strategy for a typical London-based B2B SaaS company trying to decide between these two platforms.

If you've read this far, you're probably serious about making paid ads work. You understand it's more complex than just boosting a post. Getting this right can be the difference between stagnating and hitting your next growth milestone. If you're a B2B SaaS founder and want an expert pair of eyes on your strategy, we offer a free, no-strings-attached 20-minute consultation. We'll look at your business, your offer, and your goals and tell you honestly which platform we think you should start with and why. There's no hard sell, just straightforward advice based on our experience running campaigns for dozens of SaaS companies like yours.