Definition
What is CPM in advertising?
CPM (cost per thousand impressions) is the amount paid for a thousand displays of an ad, whether anyone clicks on it or not. It is calculated by dividing spend by the number of impressions, then multiplying by 1,000. CPM buys exposure rather than visits: it is used mostly for awareness campaigns, where the goal is to be seen by a precise audience.
Where you pay by CPM
CPM is common on social networks, in display and in video. Meta advertising is billed mainly on impressions, which sets it apart from search advertising billed per click. Even when you choose a sales objective, the price paid to Meta is therefore read first as a CPM.
The "M" comes from the Latin word mille: CPM always refers to a batch of a thousand displays, never to a single one.
What CPM measures and what it does not
CPM says what an audience's attention costs, not what the audience does with it. An impression is not a person: the same person can see the ad several times. Reach (the number of distinct people) therefore stays lower than the number of impressions.
A low CPM can come from placements that few people look at. A rising CPM can come from an audience that is too narrow, which exhausts the budget and pushes the cost up.
When CPM is the right fit
CPM fits when the goal is to be seen: introducing a brand in a new market, announcing a season, staying present between two purchases. For a business looking for enquiries, it is rarely the right model. Its effect does not show in clicks. It has to be measured another way (with an incrementality test, for example), which takes a budget and a duration most engagements do not have.
CPM = (spend ÷ impressions) × 1,000
CPM connects to CPC through the click-through rate: CPC = CPM ÷ (1,000 × CTR). A $10 CPM with a 1% CTR gives a $1 CPC.
A performance venue spends $600 on Meta to announce its season. The ad is displayed 80,000 times: its CPM is $7.50. That figure says the season was seen at a certain price. It does not say how many tickets were sold: you need the cost per ticket sold for that.
We read CPM as a price of exposure, never as proof of results. In our reports, impressions come after leads, sales and cost per acquisition: a channel is judged on its commercial result, not on how many times it was seen.
On Meta, we still watch CPM closely. When it rises, the same spend buys fewer displays and the cost per sale can follow.
Not to be confused with
- CPC
- CPC is paid only when someone clicks. CPM is paid on display, whether there is a click or not.
- PPC
- PPC is the pay-per-click billing model, the opposite of CPM: it buys visits rather than exposure.
- Reach
- Impressions count displays; reach counts people. CPM is calculated on impressions: it does not say how many different people saw the ad.
Related concepts
Further reading
- Meta advertising: how to diagnose a Facebook and Instagram account
- Social media advertising: choose, concentrate, measure
- Digital ad spend: what the market tells a small business
- Executives: proving your advertising caused the sale
Related services
Frequently asked questions
What is a good CPM?
No CPM holds for everyone: it varies with the platform, the audience targeted and the time of year. A CPM is judged on what it produces next (clicks, sales, a measured rise in demand), never on its own.
Is CPM cheaper than CPC?
The two do not compare directly: one buys a thousand displays, the other a visit. To compare them, bring both back to the cost of a sale.
