CPM Calculator

What is CPM?

CPM stands for cost per mille, from the Latin word for thousand. It's the price of 1,000 ad impressions, where an impression is one showing of your ad on a screen. CPM is the standard way to price and compare display, video, social and connected-TV advertising, and it's how most awareness campaigns are bought.

Because it measures exposure rather than results, CPM is best read alongside what the impressions achieve. That's why this calculator can also estimate clicks, effective cost per click and effective cost per acquisition.

CPM formulas

CPM links three numbers. If you know any two, you can work out the third, which is what the "Solve for" switch above does:

Worked examples

• Finding CPM: a campaign cost $2,500 and delivered 500,000 impressions. $2,500 ÷ 500,000 × 1,000 = $5.00 CPM.
• Planning a budget: you want 1.2 million impressions and the quoted CPM is $8.50. 1,200,000 × $8.50 ÷ 1,000 = $10,200.
• Estimating delivery: you have $3,000 and expect a $12 CPM. $3,000 ÷ $12 × 1,000 = 250,000 impressions.

CPM vs CPC vs CPA

These are three ways to price the same advertising. The difference is which outcome you pay for, and so who carries the risk if the ads don't perform:

To compare offers priced differently, convert them with your click-through rate (CTR):

Example: a $5 CPM with a 0.9% CTR works out to $5 ÷ (0.009 × 1,000) = $0.56 per click. If another platform charges $0.80 per click for similar traffic, the CPM buy is cheaper, as long as the CTR holds.

What affects CPM?

CPM is set by auctions or negotiated rates, and it varies widely. Numbers from someone else's campaign are rarely a reliable benchmark for yours. The main factors are:

• Audience: narrow, high-value audiences (for example, senior decision-makers or people in high-income markets) attract more bidders and cost more to reach.
• Competition and season: CPMs typically rise in the fourth quarter as retailers compete for holiday shoppers, and fall in quieter months.
• Format and placement: video, premium sites and prominent placements usually cost more than standard display banners.
• Country: prices differ greatly between markets because of differences in advertiser demand.
• Ad relevance: on platforms like Meta, ads people engage with can win auctions at lower cost than ignored ones.

Reach and frequency

Impressions aren't people. If each person sees your ad three times on average, 500,000 impressions reach about 166,667 people:

Frequency is a balancing act. Too low and people may not remember the ad; too high and they tire of it, engagement drops, and some platforms make each impression more expensive. Most ad platforms report actual reach and frequency, so use their figures when you have them and this estimate for planning.

Viewable CPM (vCPM)

Not every impression is actually seen. An ad might load at the bottom of a page nobody scrolls to. Viewable CPM counts only impressions that meet the industry viewability standard set by the Media Rating Council: at least 50% of the ad on screen for at least one continuous second for display ads, or two seconds for video.

vCPM prices look higher than standard CPM because fewer impressions qualify, but they can be better value. When comparing offers, make sure you're comparing CPM with CPM, or vCPM with vCPM.

Common CPM mistakes

• Chasing the lowest CPM. Very cheap impressions often come from low-quality sites, poor placements or invalid traffic. A higher CPM that produces real attention and clicks can be the better deal. Check effective CPC and CPA, not just CPM.
• Comparing across different goals. A reach campaign and a conversion campaign on the same platform will have very different CPMs, because the platform shows them to different people.
• Confusing impressions with people. Budget for reach and frequency separately. A million impressions shown to 50,000 people is a very different campaign from one shown to 500,000.
• Ignoring viewability and brand safety. Ask for viewability rates and placement reports, especially for programmatic display.