What is CPM?
CPM stands for cost per mille — "mille" is Latin for thousand. It's the price an advertiser pays for 1,000 impressions (times an ad is shown). CPM is the standard way to buy and compare display, video, social and connected-TV advertising, because it puts campaigns of every size on the same scale.
CPM formula
Total cost = CPM × Impressions ÷ 1,000
Impressions = Total cost ÷ CPM × 1,000
Example: you spend $2,500 and your ads are shown 400,000 times.
- CPM = $2,500 ÷ 400,000 × 1,000 = $6.25
- With a $5,000 budget at the same CPM you'd get $5,000 ÷ $6.25 × 1,000 = 800,000 impressions
CPM, CPC, CTR, CPA and ROAS
CPM tells you what attention costs. The other metrics tell you whether that attention turned into results:
| Metric | Formula | What it tells you |
|---|---|---|
| CTR (click-through rate) | Clicks ÷ Impressions × 100 | How compelling the ad is |
| CPC (cost per click) | Cost ÷ Clicks | What each visitor costs. Also CPC = CPM ÷ (CTR × 10) |
| Conversion rate | Conversions ÷ Clicks × 100 | How well the landing page sells |
| CPA (cost per acquisition) | Cost ÷ Conversions | What each sale or lead costs |
| ROAS (return on ad spend) | Revenue ÷ Cost | Revenue per $1 of ads. 3.0 = $3 back per $1 |
A low CPM isn't automatically good: cheap impressions with a tiny CTR can produce a higher CPC and CPA than a premium placement. Judge campaigns on CPA and ROAS, and use CPM to plan reach and budget.
What is a good CPM?
CPMs vary by platform, audience, ad format, country and season — Q4 holiday CPMs are often 30%–50% higher than in Q1. These are broad US ranges advertisers commonly see; use your own account data as the real benchmark.
| Channel | Typical CPM range (US) |
|---|---|
| Google Display Network | $2 – $10 |
| Meta (Facebook & Instagram) | $8 – $20 |
| YouTube | $5 – $15 |
| TikTok | $4 – $12 |
| $25 – $60+ | |
| Connected TV / streaming | $20 – $45 |
| Programmatic display (open exchange) | $1 – $5 |
CPM vs. RPM for publishers and creators
If you run a website or YouTube channel, advertisers' CPM is not what you earn. Platforms take a share, and not every page view shows an ad. RPM (revenue per mille) is your earnings per 1,000 page views or video views:
YouTube, for example, passes 55% of long-form ad revenue to creators, and RPM also counts views where no ad ran — so RPM is typically well below the advertiser CPM. To estimate earnings, enter your expected RPM as the "CPM" and your monthly views as "impressions" and solve for total cost.
How to lower your CPM
- Broaden targeting. Very narrow audiences are more competitive and expensive.
- Improve ad relevance. Platforms reward ads that get engagement with cheaper delivery.
- Refresh creative. Ad fatigue raises CPM as frequency climbs.
- Test placements and timing. Automatic placements and off-peak periods are often cheaper.
- Optimize for the right goal. Reach and awareness objectives buy impressions cheaply; conversion objectives pay more per impression but can lower CPA.
Frequently asked questions
How do you calculate CPM?
Divide the total cost of the campaign by the number of impressions, then multiply by 1,000. $500 for 100,000 impressions is a $5 CPM.
How many impressions will $1,000 buy?
Divide $1,000 by the CPM and multiply by 1,000. At a $10 CPM you get 100,000 impressions; at a $5 CPM, 200,000.
How do I convert CPM to CPC?
CPC = CPM ÷ (CTR × 1,000), with CTR as a decimal. A $10 CPM with a 1% CTR works out to $10 ÷ 10 = $1.00 per click.
What does ROAS of 4 mean?
You earned $4 in revenue for every $1 spent on ads. Whether that is profitable depends on your product margins — with a 25% margin, a ROAS of 4 only breaks even.
Is CPM the same as RPM?
No. CPM is what advertisers pay per 1,000 impressions. RPM is what a publisher earns per 1,000 page or video views after the platform's share and unsold inventory.