What Is CPM in Advertising?

CPM stands for Cost Per Mille. “Mille” means one thousand, so CPM represents the cost of delivering 1,000 ad impressions.

An impression generally represents an instance in which an ad is served or displayed. CPM is widely used in display advertising, video advertising, programmatic advertising, social media advertising and other impression-based media buying environments.

CPM Example

What Is CPC in Advertising?

CPC stands for Cost Per Click. It measures how much an advertiser pays, on average, for each click generated by an advertisement.

CPC is particularly relevant for campaigns where generating website visits, leads or other click-based actions is an important objective.

CPC Example

CPM vs CPC: The Main Difference

The simplest way to understand the difference is to look at what each metric uses as its denominator.

CPM vs CPC Example: How Are They Connected?

CPM and CPC are not completely separate concepts. You can connect them using CTR (Click-Through Rate).

Imagine a campaign generates 100,000 impressions at a $5 CPM.

The total advertising cost would be:

Now suppose the campaign has a 1% CTR. A 1% CTR means approximately 1,000 clicks from 100,000 impressions.

How to Calculate CPC From CPM and CTR

If you know the CPM and CTR, you can calculate the implied or effective CPC using this formula:

When using this formula, express CTR as a decimal rather than a whole percentage.

How Does CTR Affect CPM vs CPC?

CTR is an important link between impression-based and click-based advertising metrics.

If CPM stays the same and CTR increases, the number of clicks generated from the same number of impressions increases. As a result, the effective CPC decreases.

Conversely, if CPM stays the same but CTR decreases, fewer clicks are generated from the same impression volume, causing the effective CPC to increase.

This illustrates why looking at CPM alone does not tell you what the eventual cost per click will be. CTR and other campaign performance factors matter too.

When Should You Use CPM Advertising?

CPM-based advertising can be useful when the primary objective is delivering impressions and reaching an audience at a particular impression cost.

CPM can be relevant for:

• Brand awareness campaigns
• Display advertising
• Video advertising
• Programmatic advertising
• Reach-focused campaigns
• Audience and inventory buying
• Campaigns where impressions are an important delivery metric

When Should You Use CPC Advertising?

CPC can be useful when clicks or website traffic are important campaign outcomes and the advertiser wants to evaluate media cost in relation to click volume.

CPC can be relevant for:

• Search advertising
• Traffic-focused campaigns
• Website acquisition campaigns
• Performance marketing
• Campaigns optimized toward clicks
• Advertising where click volume is an important KPI

CPM vs CPC: Don’t Ignore the Campaign Objective

Choosing between CPM and CPC should not be based only on which number looks smaller.

A $2 CPC is not necessarily better than a $5 CPC, and a $4 CPM is not necessarily better than a $10 CPM. The numbers have different denominators and can represent completely different campaign outcomes.

For example, an advertiser might be willing to pay a higher CPM if the campaign reaches a highly relevant audience and produces strong business results. Similarly, a low CPC does not automatically mean a campaign is successful if the resulting visitors do not convert.

Other Metrics to Consider Alongside CPM and CPC

CPM vs CPC From an Advertiser and Publisher Perspective

CPM and CPC can also be understood differently depending on whether you are buying or monetizing advertising.

Common Mistakes When Comparing CPM and CPC

1. Comparing the numbers directly

CPM and CPC use different units. Comparing “$5 CPM” directly with “$0.50 CPC” does not tell you which campaign is cheaper or more effective.

2. Ignoring CTR

For impression-based campaigns, CTR can have a significant effect on the resulting effective CPC.

3. Looking only at clicks

A large number of clicks does not necessarily mean that a campaign is generating valuable customers or leads.

4. Ignoring conversion performance

If the ultimate objective is generating leads or sales, metrics such as CPA, CPL, conversion rate and revenue may provide more useful context than CPC alone.

5. Confusing CPM with total campaign cost

CPM is a normalized cost metric representing the cost per 1,000 impressions. It is not necessarily the total amount spent on a campaign.

CPM or CPC: Which Metric Should You Focus On?

CPM vs CPC Advertising: Final Takeaway

CPM and CPC answer different questions.

CPM asks: How much does it cost to deliver 1,000 impressions?

CPC asks: How much does each click cost on average?

CPM is particularly useful for understanding impression-based media costs, while CPC is useful for evaluating the cost associated with generating clicks. CTR connects the two metrics and helps explain how an impression-based campaign can translate into an effective CPC.

However, neither CPM nor CPC should be treated as a standalone measure of campaign success. The most appropriate metric depends on the campaign objective and should ultimately be considered alongside conversion, lead, revenue and return metrics where relevant.

Frequently Asked Questions About CPM vs CPC