CPM stands for cost per mille, or cost per thousand impressions. Instead of paying when someone clicks your ad, you pay for the number of times it is shown.
In Google Ads, CPM bidding is for Display and YouTube campaigns, not Search. It suits campaigns where being seen is the goal. Used for the wrong goal, it becomes an efficient way to pay for attention that never turns into anything.
Key takeaways
CPM means you pay per 1,000 impressions, whether or not anyone clicks.
On the Display Network, Google uses viewable CPM. A display ad counts as viewable when 50% of it is on screen for at least 1 second.
Target CPM is for video campaigns and optimises for reach among unique users.
Search ads do not use CPM. For visibility on Search, Google offers Target Impression Share.
Compare CPM and CPC on the same terms by converting to effective cost per click or cost per result.
What does CPM mean in Google Ads?
Google's glossary defines CPM as "a way to bid where you pay per one thousand views (impressions)". The maths is simple:
CPM = (total cost / impressions) x 1,000
Example:
Spend $450
Impressions 150,000
CPM ($450 / 150,000) x 1,000 = $3.00Which CPM bidding options does Google Ads offer?
| Bid strategy | Where it works | How it works | Best for |
|---|---|---|---|
| Viewable CPM (vCPM) | Display Network campaigns | You set the most you will pay per 1,000 viewable impressions | Awareness on chosen sites, apps and audiences |
| Target CPM (tCPM) | Video campaigns | You set an average CPM and Google optimises for unique reach | Reaching as many different people as possible on YouTube |
| CPM | YouTube and the Display Network | You pay based on the number of impressions | Visibility-focused video and display campaigns |
| Target Impression Share | Search campaigns | Automated bidding to appear at the top, absolute top or anywhere on the results page, still charged per click | Visibility on Search |
Google's bid strategy guide recommends vCPM when "your ads are designed to increase awareness, but not necessarily generate clicks or traffic."
What counts as a viewable impression?
Not every impression is seen. Someone may scroll past before an ad loads, or the ad may sit below the visible part of the page. Google's viewable CPM guidance sets the standard:
| Ad type | Counts as viewable when |
|---|---|
| Display ad | 50% of the ad is on screen for 1 second or longer |
| Video ad | 50% of the ad plays continuously on screen for 2 seconds or longer |
Google also notes that "Max. CPM is no longer available as a bid strategy." On Display campaigns, CPM bidding means paying for viewable impressions, which protects you from paying for ads nobody could have seen.
How do you compare CPM with CPC?
Convert them to the same unit. If you know your click-through rate, you can work out what a CPM campaign is effectively paying per click:
Effective CPC = CPM / (CTR x 1,000)
Campaign A, CPM bidding: CPM $3.00, CTR 0.40% -> $3.00 / 4 clicks = $0.75 per click
Campaign B, CPC bidding: CPC $1.20
Campaign A is cheaper per click. But if Campaign B converts 5% of clicks and
Campaign A converts 1%, the cost per conversion is:
A: $0.75 / 0.01 = $75
B: $1.20 / 0.05 = $24The figures above are illustrative. The lesson is that the cheapest impressions or clicks rarely tell you which campaign is cheaper at producing customers.
| Question | CPM or vCPM | CPC |
|---|---|---|
| What you pay for | Impressions, or viewable impressions | Clicks |
| Main goal | Awareness and reach | Traffic and actions |
| Main risk | Paying for exposure that does not change behaviour | Paying for clicks that do not convert |
| Useful metrics | Viewable impressions, unique reach, frequency, brand lift, branded search | CTR, conversion rate, cost per conversion |
| Typical campaigns | Display and YouTube | Search, Shopping and performance Display |
When is CPM worth using?
You are launching a brand or product and need people to recognise it before they search.
You want to stay visible to past visitors or customers with a controlled frequency.
You have strong visual or video creative that works without a click.
You are buying specific placements, such as sites or channels your audience trusts.
You can measure lift, for example through brand lift studies, branded search volume or direct traffic.
If you need enquiries or sales this month, CPC or conversion-based bidding on Search is usually a better start. We compare the main paid channels in Google Ads or Facebook Ads: which is better for your business?
How do you stop wasting money on impressions?
Use viewable CPM on Display, so you only pay for impressions that meet the viewability standard.
Review where your ads appeared. Check placement reports and exclude sites, apps or channels that are irrelevant or unsafe for your brand.
Set frequency caps so the same people do not see your ad dozens of times.
Refresh creative regularly before performance declines from fatigue.
Define the audience before the budget. Broad reach at a low CPM is only good value if the right people are in it.
Measure what happens next: branded searches, direct visits and conversions from people who saw but did not click.
Your landing pages still matter for awareness campaigns, because people who see an ad often visit later. If visits do not turn into enquiries, see why conversion rates drop when rankings look fine or our CRO and analytics work.
Should you run awareness ads or build organic visibility first?
It depends on your timeline. Paid impressions stop the day the budget stops. Search visibility builds more slowly but keeps working. Many businesses use a small awareness budget to create demand while SEO captures the searches it creates. For that trade-off, read should you invest in SEO or broader digital marketing? or talk to us.
Frequently asked questions
What is a good CPM in Google Ads?
There is no universal good CPM. It varies by audience, placement, format, country and season. Judge CPM against your own goals: viewable reach, frequency and the actions that follow, not against an industry average.
Does Google charge per impression on Search ads?
No. Search campaigns charge per click. If you want more visibility on Search, Google offers Target Impression Share bidding, which aims to show your ad in chosen positions but still charges per click.
What is the difference between CPM and vCPM?
CPM counts impressions served. Viewable CPM only counts impressions measured as viewable: for display ads, at least half the ad on screen for one second or longer. On Display campaigns, Google uses viewable CPM.
Is CPM or CPC cheaper?
Neither is cheaper by default. Convert CPM into effective cost per click or, better, cost per conversion. A low CPM with a very low click-through or conversion rate can be more expensive than a higher CPC.
