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Performance & Measurement
3 min read
CPM, or cost per mille, is the price of one thousand ad impressions — what you pay for exposure rather than for clicks or conversions. It is the currency of awareness and reach campaigns, and the baseline unit for comparing the cost of inventory across the market.
You buy impressions. You pay to have your ad shown, not clicked.
Price is per thousand. CPM expresses that cost in blocks of 1,000 views.
The auction sets it. Demand for the audience and placement moves the price.
It measures reach cost. Lower CPM means cheaper exposure to your audience.
Awareness campaigns. When the goal is being seen, not immediate action.
Reach buys. Getting a message in front of many people.
Benchmarking. Comparing inventory cost across placements.
Brand building. Sustained presence over direct response.
Reach efficiency. It shows how cheaply you can build awareness.
Market comparison. It normalises cost across very different placements.
Planning. It helps forecast the exposure a budget can buy.
Exposure is not impact. Being shown is not the same as being noticed.
Viewability. A served impression may never actually be seen.
Quality varies. Cheap CPM can mean low-quality inventory.
Weak for response. For conversions, CPA or ROAS tell you more.
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