A good UK Google Ads agency costs somewhere between £1,000 and £5,000 a month, or 5 to 10 per cent of your ad spend, and it should be able to tell you your cost per qualified lead without being asked.
That is the short version. The rest of this page is about what sits behind those two numbers.
Search for "google ads agency" and almost everything that ranks is a list of agencies, usually written by an agency that puts itself at the top. The one proper buyer's guide in the UK results, from Priority Pixels, is a fair piece. But it stops at the pricing model and says little about what a 2026 retainer should actually contain, or how the newer automated campaign types change the job. So this starts there.
What a Google Ads retainer should include in 2026
A Google Ads retainer should pay for five things you can check, not for hours and "optimisations" you cannot. A management invoice that lists activity tells you the agency was busy. It does not tell you whether your leads got cheaper. Ask for these five in writing before you sign.
- An account build, not a boosted button. Campaigns split by intent, ad groups tight enough that one ad speaks to one search, sitelinks and call assets in place, a tracking template on every URL. A good agency rebuilds a messy account instead of nursing it.
- Conversion tracking that counts qualified leads. A form fill is not a customer. The agency should count a phone call over a set length, a booked enquiry form and a WhatsApp message as the conversions. The "view our number" clicks stay out. Whether to count a call, a form or a WhatsApp enquiry is a real decision, and it decides what the bidding algorithm learns from.
- A negative keyword list written before launch. Not after the first month of waste. The list is the thing that stops a plumber paying for "plumbing apprenticeship". It matters more now, because the automated campaign types match far wider than old exact-match keywords did.
- A weekly search terms review. Pulling the search terms report and cutting the junk is a ten-minute job that most underpriced accounts never get. It is where you find out what Google actually charged you for.
- A monthly report built on cost per qualified lead. Not impressions, not clicks, not click-through rate in the headline position. One number, tracked month on month, with the search terms and the wasted spend shown underneath it.
Conversion signal quality is the quiet thing all five are serving. Smart Bidding spends your money chasing whatever you told it a conversion is. So if that signal is a button click and not a real enquiry, the agency is paying Google to find you more button clicks. This bites hardest at the small end. A £500 a month account cannot carry a £1,500 retainer, and the fee has to fit the spend or the maths never works.
What a UK Google Ads agency charges
Most UK agencies charge one of two ways: a percentage of your ad spend, or a flat monthly fee. The percentage model usually sits at 5 to 10 per cent. Whitehat's UK pricing roundup says 83 per cent of businesses spending £1,000 to £100,000 a month pay in that band. Priority Pixels quotes a wider 10 to 20 per cent. The gap is real, not a contradiction: small budgets sit at the top of the range because the work does not shrink with the spend, and large budgets sit at the bottom.
The flat fee is the other model, and it is where the honest numbers live. Whitehat puts full-service management at £3,000 to £5,000 a month and warns that scope is "severely constrained" at the £500 to £750 level. Percentage deals usually carry a minimum monthly fee of £1,000 to £2,000 underneath them, which is the agency's revenue floor when your spend dips.
| Fee model | Typical UK figure | Suits | The catch |
|---|---|---|---|
| Percentage of spend | 5 to 10% (sometimes 10 to 20% on small budgets) | Spend that moves up and down month to month | Rewards the agency for raising your budget, not your profit |
| Flat monthly fee | £1,000 to £5,000 depending on scope | Steady spend and a defined scope | Rewards the agency for keeping you, whatever the result |
| Percentage with a minimum | £1,000 to £2,000 floor | Medium accounts hedging both ways | You pay the floor in a slow month even if spend is tiny |
Where you are also changes the bill. Whitehat's regional averages run from about £1,200 a month in London down to about £830 in Wales and Northern Ireland. London agencies charge 30 to 45 per cent more than equivalent work in the north. A freelancer undercuts an agency by 30 to 40 per cent, with the trade-off that there is one person and no cover.
Neither fee model is wrong. You just need to know which incentive you are buying, and the same two models and the same question turn up when you hire a UK SEO agency. On a percentage deal, a budget rise is a pay rise for the agency, so the pressure to spend more is built in. On a flat fee, the agency gets paid whether the account improves or not, so the pressure to improve has to come from your reporting.
The contract around the fee matters as much as the number. Priority Pixels describes a one to three month notice period as normal and flags a twelve-month lock-in with heavy exit penalties as a reason to walk away. A short notice period is the agency telling you it expects to earn the renewal. Ask for a two or three month trial before any longer term, and check what happens to the account and the creative on the day you give notice, because that is when "we own the account" stops being an abstract worry.
How to tell a good agency from an expensive one
You can separate a good agency from an expensive one with three checks: who owns the account, what the monthly report leads with, and how they talk about automation. None of them needs you to understand the platform.
Account ownership comes first. The Google Ads account must be created in your name or your own manager account, and you must keep it, with all its history, when you leave. Priority Pixels calls this non-negotiable, and they are right. An agency that owns your account owns your conversion history, and that history is what every bidding strategy is built on. If leaving means starting from zero, you were renting, not building.
The report is the second check. A good one opens with cost per qualified lead and the search terms you paid for. A weak one opens with impressions and a rising click-through rate, which look like progress and cost you nothing to feel good about. Attribution is the trap underneath the numbers. Most reports still credit the last click, so a lead that found you through an organic search and then clicked a brand ad gets filed as a paid win. Ask how much of the "performance" is branded search, and how Performance Max is reporting across its channels. PMax rolls Search, Shopping, Display and YouTube into one line that can quietly take credit for demand you already had.
The third check is the one most buyers skip. If the agency also runs your Meta ads, ask how they structure the account and what they do about lead quality. A Meta lead form left on default settings generates junk at volume. The agency that cannot describe how it filters that junk is the one that will bill you for it.
What a good agency does with AI Max and Performance Max
A good agency treats AI Max and Performance Max as tools to be configured and contained, not switched on and trusted. Both hand control to Google in exchange for reach, and both can work well once the account feeds them clean conversion data. The skill is in the setup, not the switch.
AI Max for Search is the newer one. Google launched it in May 2025 as a one-click bundle of broad matching, auto-generated headlines and final URL expansion. It claims advertisers "will typically see 14% more conversions", rising to 27 per cent for campaigns still leaning on exact and phrase keywords. Those are Google's own figures, and the catch is in the bundle. Final URL expansion can send a paying click to any page on your site, and brand controls are off until someone sets them. The pre-flight matters. A good agency decides what to turn off before it turns AI Max on, keeps the search terms visible, and sets the brand and URL controls instead of inheriting the defaults.
The controls Google ships with AI Max are the ones to use on day one: brand inclusions and exclusions so the campaign does not bid on competitor names you did not choose, locations of interest at ad group level, and the new search terms visibility so you can still read what each match type actually triggered. An agency that enables AI Max and then shows you a conversion lift without showing you the search terms underneath it is asking you to trust the 14 per cent on faith.
There is a deadline attached to this. Google is folding Dynamic Search Ads into AI Max: new DSA campaign creation ends in January 2027 and automatic migration of what is left begins in February 2027. If your account still runs DSA, that is a change to plan for, not to be surprised by.
Performance Max is the older automation, and the choice against Standard Shopping is a real one for retailers. PMax buys cheaper clicks, which is exactly why it is easy to oversell.
xychart-beta
title "Average UK cost per click by campaign type (Whitehat, 2025-2026)"
x-axis ["Search", "Shopping", "Performance Max", "Display"]
y-axis "Cost per click (GBP)" 0 --> 5
bar [4.0, 2.25, 1.0, 0.85]
The chart uses the midpoints of Whitehat's ranges: Search at £3 to £5 and up, Shopping at £1.05 to £3.46, Performance Max at £0.66 to £1.31, Display at £0.50 to £1.20. A cheaper click is not a cheaper customer, though. Standard Shopping gives you the product-level and search-term control that PMax hides, and for a small catalogue that control is often worth more than the lower CPC. The same logic applies to broad match. It earns its place once there is enough conversion volume for Smart Bidding to learn, and it burns money before then.
The limits no agency can bill away
No agency can bill away two things happening to Google Ads right now, and you should be suspicious of one that pretends otherwise. The first is that ads are moving into the AI answers themselves. The second is that clicks keep getting dearer.
Google began putting Search and Shopping ads inside AI Overviews from May 2025, and is testing them in AI Mode. Campaigns running Performance Max, Shopping or broad match, which now includes AI Max, are automatically eligible for those placements. You do not really opt in, and there is no clean opt-out. So part of your budget now serves a slot above an AI answer that may give the searcher what they wanted without a click. Winning the organic side of that answer is a separate discipline, generative engine optimisation.
The cost side is simpler and harder to fix. LocaliQ's benchmark data, covering April 2024 to March 2025, put the average cost per click up 12.88 per cent to $5.26, with 87 per cent of industries seeing a rise. Part of that is competition, and part is Google now showing more than one ad per page. Part is the automation itself.
"We've seen sharper increases on campaigns with smart bidding. Google has direct control over these CPCs." Katia Hausman, VP of Product, LocaliQ
That is the honest frame for the whole hire. A good agency does not promise to beat the auction. The auction is getting more expensive for everyone, and the automation that sets the prices is the same automation you are being asked to trust. What a good agency does is build the account so the money chases qualified leads, keep the controls set, and report the one number that survives every platform change: what a real customer costs you.
If a prospective agency cannot tell you who will own the account, how it defines a conversion, and what its report leads with, you have your answer before you have seen a single campaign. Those three are the whole job in miniature, and they sit at the centre of choosing a digital marketing agency of any kind.
If you want that checked for your own account before you commit to anyone, our paid media team will review the setup and the numbers with you. Or get in touch with your spend and your target cost per lead.