How CPM is calculated
CPM stands for cost per mille — mille being Latin for thousand — and measures what you pay for every 1,000 ad impressions. The formula is (cost ÷ impressions) × 1,000. Spend $1,500 to earn 300,000 impressions and your CPM is $5. It is the dominant pricing model for display, video and social advertising because impressions are the base unit of reach, and expressing cost per thousand keeps the numbers readable. This calculator also shows the raw cost per single impression and lets you reverse the maths to see what a bigger budget buys.
CPM from both sides
CPM matters to two different people. Advertisers use it to compare the cost-efficiency of placements — a lower CPM means cheaper reach, all else equal. Publishers and creators use it as a revenue metric: a channel or newsletter selling ads at a $20 CPM earns $20 for every 1,000 impressions it delivers. The same number, read two ways. If you are buying, you want CPM low; if you are selling ad space, you want it high. Knowing your CPM lets you price inventory and forecast either ad costs or ad income.
What moves CPM
CPMs vary widely by platform, audience and timing. Highly targeted or premium audiences (B2B decision-makers, high-income niches) command higher CPMs because advertisers value them more. Seasonality is huge — CPMs spike in Q4 around the holidays and dip in January. Format matters too: video and connected-TV CPMs run higher than standard display. Ad quality, viewability, competition in the auction and audience geography all push the number around. Because so many factors feed in, CPM is best tracked as a trend for your own placements rather than compared to a single benchmark.
Using CPM for planning
CPM is most useful for forecasting. Once you know a typical CPM for a channel, you can estimate the reach a budget will buy — the reverse calculation this tool provides — or the cost to hit a reach goal. Pair it with click-through and conversion rates to judge whether cheap impressions actually deliver results, since low CPM alone does not guarantee value. These tools use published benchmark rates and the figures you enter — every rate is an editable assumption. They are rough estimates for planning, not a guarantee: actual creator earnings vary widely with niche, audience, geography, season and platform payout changes.
Frequently asked questions
How do I calculate CPM?
Divide the campaign cost by the number of impressions, then multiply by 1,000. A $1,500 campaign delivering 300,000 impressions has a CPM of $5. This calculator does the maths both ways.
What is a good CPM?
It varies enormously by platform, audience and season — social display CPMs might run $2–$10, premium video far higher. Compare against your own channel's history rather than a universal figure.
What is the difference between CPM and CPC?
CPM charges per 1,000 impressions regardless of clicks; CPC (cost per click) charges only when someone clicks. CPM suits awareness campaigns; CPC suits direct-response campaigns focused on action.
How do I estimate reach from a budget?
Divide your budget by the CPM and multiply by 1,000. This calculator's 'impressions for budget' result does exactly that at the CPM you enter.