Cost per mille (CPM) is the cost of obtaining one thousand ad impressions. It is commonly used in display, video, programmatic, and other impression-based advertising to compare media costs across placements or campaigns.
Quick Answer
CPM = (Total Advertising Cost Γ· Impressions) Γ 1,000
Inputs Explained
Advertising cost is the amount spent for the impressions being analyzed. Impressions is the number of times the ad was served or counted according to the platform's reporting rules. βMilleβ means one thousand.
How to Use the CPM Calculator
- Enter the total campaign or placement cost.
- Enter the number of impressions.
- Calculate the equivalent cost per 1,000 impressions.
- Use the same time period and reporting definitions when comparing CPMs.
Worked Examples
Example 1
$200 spent for 100,000 impressions gives CPM = ($200 Γ· 100,000) Γ 1,000 = $2.00.
Example 2
$750 spent for 250,000 impressions gives a CPM of $3.00.
Example 3
If 50,000 impressions cost $400, CPM = ($400 Γ· 50,000) Γ 1,000 = $8.00.
CPM Examples
| Spend | Impressions | CPM |
|---|---|---|
| $100 | 50,000 | $2.00 |
| $300 | 100,000 | $3.00 |
| $1,000 | 200,000 | $5.00 |
CPM vs CPC
CPM describes impression cost, while CPC describes click cost. An advertiser can have a low CPM but a high CPC if few people click. Conversely, a higher CPM can produce an efficient CPC when the placement receives a strong click-through rate.
Common Mistakes
- Forgetting to multiply by 1,000.
- Using clicks instead of impressions in the CPM formula.
- Comparing gross spend with net impressions from a different period.
- Assuming CPM alone proves whether an advertising campaign is profitable.
Important
This calculator is for general informational purposes and is not financial, investment, or advertising advice. Advertising platforms can use different impression definitions, billing models, adjustments, and reporting windows.