Google's conversion count is not your lead count

Ask an advertiser how many leads a campaign produced last month and you get one number. Ask the business owner the same question and you get a different one. Nobody is lying. The two numbers are counting different things, and the distance between them is usually the most useful fact about the account.

What Google counts

Google Ads counts conversion actions: a tag fired, or an offline conversion you imported. It attributes each one back to the click that earned it, which is why a conversion can appear against a day on which nothing happened in your inbox. It counts what the browser told it, and where consent or cross-device gaps stop the browser telling it anything, it can model the rest.

That is a reasonable thing to count. It is not the number of people who contacted the business.

The four places the gap opens

1. One person, counted twice. Somebody fills in the form, does not hear back fast enough, and fills it in again. On the Every conversion setting that is two. In the inbox it is one person who is now slightly annoyed.
2. Spam and tests. Form spam converts beautifully. So does the developer testing the form, and the agency checking the tag still works. All of it counts.
3. Modelled conversions. Where a visitor declines analytics cookies or converts on another device, Google estimates. Estimates belong in a bidding signal. They do not belong in an invoice line that says "leads: 47".
4. Enquiries no tag ever sees. The WhatsApp message, the phone call from the number in the ad, the person who walked in because they saw you last week. For a lot of local businesses this is most of the enquiries, and none of it is in the conversion column.

Note that two of those push Google's number up and two push it down. That is why "Google over-reports" is as wrong as "Google under-reports" — the errors do not cancel, they just make the number unreliable in an unknown direction.

Count the thing you actually care about

The number worth reporting is the one a human could act on: enquiries that reached the business, deduplicated, with spam and tests removed, plus the channels that never touch a tag.

Deduplicating is where this usually goes wrong. Real form data arrives as +44 7758 854220, 07758854220 and 447758854220 from the same person, and matching the raw strings finds almost none of the duplicates. We keep the last nine digits of a phone number as the key, and lower-case emails. It is a blunt rule and it catches nearly everything.

Then look at the gap on purpose

Once you have both numbers, the difference stops being an embarrassment and becomes a diagnostic:

• Google's count much higher than the verified count, and the extra is spam or duplicates? Your bidding is optimising towards junk, because Smart Bidding buys more of whatever the tag rewards it for.
• Google's count much lower? Something is not firing. A form that redirects too quickly, a thank-you page that changed, a tag that never loads on mobile.
• Google's count lower and the phone is ringing? Nothing is broken. You are simply measuring a fraction of the demand you are paying for, and any ROAS figure calculated from it is wrong by however large that fraction is.

This is the reason our client reports put verified leads in the headline and keep Google's number beside it rather than replacing it. Cost per lead is calculated against the verified figure, because that is the one a business owner recognises. The gap gets its own line, because it is a finding.

What this does not mean

It does not mean you should turn off conversion tracking, or stop importing offline conversions, or feed the bidding algorithm a hand-counted number once a month. Google's count is what the bidding runs on and it needs to keep running. It means the number you report to a client and the number you optimise on are allowed to be different numbers, as long as you know which is which.