ScaleyCost per Impression in Google Ads (CPM and vCPM)
What cost per impression means, how viewable CPM works in Google Ads, the formula, and why most stores still pay per click.
Written and reviewed by Christopher Krassnig
Published Last checked
Cost per impression is what you pay each time your ad is shown. Ad platforms quote it per 1,000 impressions, called CPM. In Google Ads you buy impressions with viewable CPM (vCPM) on the Display Network: you pay only when at least 50% of the ad is on screen for 1 second or longer.
Also called: CPM, cost per thousand impressions, viewable CPM (vCPM)
The CPM Formula
CPM = cost / impressions x 1,000. Cost per single impression = CPM / 1,000.
So a $5 CPM means each impression cost half a cent. CPM is a way to compare reach costs across campaigns, even campaigns you pay for by click.
How Google Ads Charges by Impression: Viewable CPM
Google defines CPM as "a way to bid where you pay per one thousand views (impressions) on the Google Display Network." Today that means viewable CPM. Google says "Max. CPM is no longer available as a bid strategy", and existing CPM bids were converted to vCPM automatically.
An impression counts as viewable "when 50 percent of your ad shows on screen for 1 second or longer for Display ads, or plays continuously for 2 seconds or longer for video ads." You bid on 1,000 viewable impressions and do not pay for ones that were not viewable.
vCPM is not available for Search Network campaigns. On Search you pay per click.
CPM vs CPC Bidding
Google's own comparison:
| Question | Viewable CPM | CPC |
|---|---|---|
| Use it if | You care more about your ads being viewed than about clicks. | You care more about clicks. |
| Your bid | The most you will pay for 1,000 viewable impressions. | The most you will pay for 1 click. |
| What you pay for | Impressions measured as viewable. | Clicks you receive. |
Google adds a tip that matters for stores: "If your main goal is online sales or visits to your website, then Maximize clicks or Maximize conversions bidding may be a better option for you." See the PPC model for how click pricing works.
Example: Comparing Two Campaigns by CPM
Made-up numbers, to show the method. A jewelry store runs a remarketing campaign on clicks: $300 spend, 60,000 impressions. CPM = $300 / 60,000 x 1,000 = $5.
It tests a brand awareness campaign on vCPM at about $3 per 1,000 viewable impressions: $300 buys around 100,000 viewable impressions.
The awareness campaign reaches more people for less per impression, but the remarketing campaign brings the sales. The store keeps remarketing on clicks and judges the vCPM test by branded searches, not direct sales. Our CPC calculator can turn a CPM and CTR into a cost per click.
Common Mistakes
Buying impressions when you want sales
Google itself says Maximize clicks or Maximize conversions may be better for online sales.
Comparing CPM with CPC directly
One is per 1,000 views, the other per click. Convert one into the other with your CTR before you compare.
Looking for CPM bidding on Search
vCPM is not available for Search Network campaigns.
Questions People Ask
What you pay each time your ad shows. Google prices it per 1,000 impressions, and today you buy impressions with viewable CPM on the Display Network.
Google's Own Pages We Quoted
Every rule, limit and size on this page comes from these pages, read on 8 October 2026. Google changes them, so check the page itself before you act.
Where to Go Next
- CPC CalculatorConvert between CPM, CTR and cost per click.
- CPM vs CPC and Other PPC MetricsEvery PPC metric pair, compared in plain English.
- How Much Does Google Ads Cost?What clicks and impressions cost a store.
- CPC for Google Ads: What You Pay per Click and How to Lower ItThe per-click side of Google Ads pricing.
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