How to estimate competitor ad spend in the UK

Every "see your competitor's ad spend" tool is estimating, and most of the advice on how to do it is written for the US market and Google only. Here's how spend estimation actually works for UK brands: what each ad platform really discloses (less than you've been told), why raw creative counts mislead, and the proxy methods we use across 147,699 tracked creatives from 164 UK brands — methods you can apply yourself with free tools and an afternoon.

The uncomfortable truth: no platform shows commercial ad spend

UK advertisers invested £46.7 billion in 2025 (AA/WARC), and not one pound of a commercial campaign's spend is published anywhere. The Google Ads Transparency Center shows creatives, dates and regions — no spend, no impressions. The Meta Ad Library shows spend ranges only for ads about social issues, elections and politics; a commercial ad shows a start date and nothing else. TikTok and LinkedIn are the same story.

So when a blog or a SaaS dashboard quotes a rival's "monthly ad budget", it is a model, not a measurement — usually built from US cost-per-click assumptions that transfer poorly to UK auctions. That doesn't make estimation hopeless. It means the honest approach is to combine the fragments each platform does disclose with behavioural proxies: how many creatives a brand keeps live, how fast it launches new ones, and where its EU-delivered ads reveal real reach. That's what the rest of this guide does.

What each ad library actually discloses

We've tested each of these in depth — see our guides to the Meta Ad Library, the Google Ads Transparency Center, the TikTok ad library and the LinkedIn Ad Library for the platform-by-platform mechanics. What follows is how to turn those fragments into a spend estimate.

Method 1: Meta's EU reach bands — powerful, but rarer than you think

Under Article 39 of the EU's Digital Services Act, any ad delivered to EU users carries a public transparency panel: who paid, the targeting parameters, and reach estimates by member state. Reach is the closest thing to a free spend signal that exists for commercial ads — multiply a reach band by a realistic CPM and you get an order-of-magnitude spend figure for that ad's EU delivery.

The UK-specific catch: Britain isn't in the EU, so UK-only campaigns get no panel at all. And in practice the panel is scarcer still. Across the 17,559 Meta ads we track from UK brands (as at 4 November 2026), only 841 (4.8%) carry an EU reach band — and of those, just 20 show reach above "<100 users". In other words, almost all the EU delivery we see from UK brands is incidental spillover, not budget. The method works brilliantly for a rival that genuinely trades in Ireland or the continent; for a UK-only advertiser it tells you nothing.

Method 2: creative counts — and the Google cap that breaks them

The most common estimation shortcut is: more live creatives = more spend. It's directionally useful — a brand paying to keep 2,000 ads in rotation is plainly spending more than one running 40 — but on Google it fails exactly where you'd want it most, on the biggest spenders.

When we tested the Transparency Center against Pets at Home, it reported about 3,000 results but stopped paginating at roughly 900 creatives — an undocumented retrieval cap we've written up in full in our Transparency Center guide. For any large advertiser, a manual count of what the tool shows you is really a count of the cap. Because we re-capture the same brands repeatedly, we accumulate creatives across many capture runs instead of one capped walk — so as at 4 November 2026 we hold 2,579 Google creatives for Cinch, 2,528 for carwow and 984 for Motorway. The first two sit far beyond anything a single Transparency Center session will show you.

Two caveats, and they matter. Creative count measures breadth, not budget: Google's responsive formats generate many registered creatives from one campaign, and a brand can run huge spend through few ads. And an accumulated count is cumulative history, not a live rotation — some of those creatives have stopped. Treat volume as a tier indicator — tens vs hundreds vs thousands — not a pounds figure, and never as "ads running today".

Method 3: launch pacing — the best free spend proxy

A better behavioural signal than how many ads a brand has is how many new ones it ships. Creative production costs money, and nobody briefs, builds and launches hundreds of new ads for campaigns they aren't funding. Launch pacing — new creatives per month, read from first-shown dates — tracks budget posture: a scale-up shows as a launch surge weeks before you'd notice anything else, and a quiet pullback shows as silence.

Here's a worked example from our data: three rivals in the UK car-selling market, counting creatives first shown in the 30 days to 4 November 2026.

Read by library size alone, Cinch and carwow look like the same business: 2,579 creatives against 2,528, a difference of nothing. Read by pacing, the story separates completely. Cinch first showed 141 new Google creatives in that month; carwow showed three, and Motorway none. carwow is sweating a large library it built earlier; Cinch is in an active production push heading into Q4; Motorway is coasting or has moved budget elsewhere. That's a budget-posture read no single library session gives you, because it needs first-shown dates collected over time rather than a one-off count.

You can run this method manually: pick a rival in the Transparency Center, filter to the last 30 days, count, and repeat monthly. Two honest warnings. First, the 900-creative cap above applies to what you can see. Second, platform-reported launch dates have their own quirks — we've documented how first-shown dates behave in our guide to how accurate ad launch data really is.

Method 4: third-party search estimators — use with care

Tools like Semrush's advertising research estimate a rival's paid-search spend by modelling the keywords it appears on, estimated click volumes and CPC data. They're useful for answering "which keywords is this brand paying to appear on?" — but the headline "traffic cost" figure is a model of US-style auction maths applied to sampled rankings. For UK brands it's best treated as a relative index (is rival A bidding on more valuable terms than rival B?) rather than a budget. And it covers search only: nothing these tools output tells you about Meta, TikTok or YouTube spend, which for many consumer brands is the larger share.

The exception: political and social-issue ads

If the advertiser you're studying runs ads about social issues, elections or politics, the game changes completely. Meta publishes actual spend ranges per ad and a downloadable Ad Library Report totalling spend by advertiser, including UK advertisers. Charities and campaign groups whose ads get classified as social-issue advertising often appear here without realising how visible their budgets are. For everyone else, this regime is a useful reminder of what full spend transparency looks like — and that commercial advertising has nothing like it.

A one-hour worksheet for sizing a rival's budget

1. Fix the entity. Find the right advertiser in the Transparency Center (verify the legal name — name search can surface the wrong company) and the right page in the Meta Ad Library.
2. Tier them by live volume. Count live creatives per platform. Note whether Google's count hits the ~900 wall — if it does, record "900+ (capped)" and treat the brand as a heavy spender.
3. Measure pacing. Count creatives first shown in the last 30 days on each platform. Repeat monthly; the trend matters more than the level.
4. Check for EU reach. If any Meta ads carry the EU transparency panel with reach beyond "<100", multiply the bands by your own CPM for a hard floor on that slice of spend.
5. Add a search-side index. Use a keyword estimator for relative paid-search intensity against other rivals — as a ranking, not a budget.
6. Write the posture, not a number. "Scaling hard on Google, steady on Meta, dark on TikTok" is defensible and actionable. "£214k/month" is neither.

Where AdRival fits

Everything above is doable by hand; the cost is repetition. The signals that matter — pacing, new launches, promotions appearing and disappearing — only exist if someone captures the libraries continuously, because Meta deletes commercial ads the moment they stop and Google caps what one session can see. That's the job we've automated: repeat capture of ads across Google, Meta, TikTok and LinkedIn for 164 UK brands — 147,699 creatives as at 4 November 2026 (112,230 Google, 17,559 Meta, 16,198 TikTok and 1,712 LinkedIn), of which the Google, Meta and TikTok creatives are qualified for offer, discount, hook and urgency — 50,982 so far. Capture runs on a weekly cadence rather than continuously, so treat every count as a snapshot with a date on it, which is why we date ours. You can see five live qualified ads for any tracked brand free on its ad library page — a reasonable place to sanity-check any estimate you've built by hand.