How long before Google Ads starts working?

Google Ads shows clicks the day the campaign goes live and enquiries within the first week if the tracking and the landing page work; a stable cost per lead takes four to eight weeks, because Smart Bidding needs around thirty conversions in a thirty-day window to learn from. Judge the account at three months, not three weeks, and judge it on cost per enquiry rather than on clicks.

Why did my cost per lead get worse in week three?

Usually the bidding strategy testing dearer searches while it learns, or the first negatives removing the cheap clicks that were never going to convert. Look at the trend over a month, not the week.

Should I change bids while it is learning?

As little as possible. Add negatives, fix tracking and the landing page, but leave the bid strategy and budget alone for at least a fortnight after each change, or the learning period never ends.

How Long Before Google Ads Works?

Day one to week two

Ads are reviewed and usually approved within a day, and the first clicks arrive within hours of approval. The first fortnight is where the strangest search terms appear, so this is the period to read the Search Terms report daily rather than weekly, adding negatives as they come. The first enquiries should appear in this window; if they do not, the first thing to check is the conversion tracking, by submitting your own form and making your own call, because an account with no conversions recorded is not the same as an account with no conversions.

Weeks three to eight

Once tracking is proven and the negatives have caught the worst of the waste, the bidding starts to learn. Google's guidance is that a Smart Bidding strategy wants around thirty conversions in a month before a target cost per action behaves, and it enters a learning period of about a week after any significant change. During this stretch the cost per enquiry moves around, sometimes sharply; that is the algorithm testing, not a verdict. The manager's job is to change as little as possible and read as much as possible.

By month three

The account should now report a cost per enquiry you can name, a Search Terms report whose top rows are all either keywords or negatives, and a first answer to the only question that matters: which of those enquiries became customers and what were they worth. If cost per enquiry is comfortably below what an enquiry is worth, the report says where spending more would buy more at the same price. If it is above, on searches that have already been cleaned, the report says so and recommends stopping or changing the sum.

What delays each stage

Ad or landing page disapprovals, which stop everything until the policy issue is fixed.
Broken tracking, which makes a working account look dead and a learning algorithm learn nothing.
A budget too small to reach thirty conversions a month, which leaves the bidding in a permanent learning period; the fix is fewer ad groups, not more patience.
Constant changes: every significant edit restarts the learning period, and an account edited daily never leaves it.
A slow or vague landing page, which turns a clean stream of clicks into a trickle of enquiries and makes the whole account look expensive.

Why three months

Month one is setup and waste removal. Month two is the bidding learning from clean data. Month three is the first month that can be judged, because it is the first where the search terms, the tracking and the algorithm were all working at once. Shorter and the judgement is made on noise; longer and a losing sum is being paid for out of hope.

Where this leads

The service this question belongs to is Google Ads management, and the longer read is our guide Why your Google Ads are not converting: the eight causes, in the order to check them.