CPM calculator

1. Pick what to work out. CPM takes ad spend and impressions. Cost tells you what a number of impressions will cost at a given CPM. Impressions tells you how many impressions a budget buys.
2. Enter the two numbers you have, from the same campaign and dates. You can type 50000 or 50,000.
3. Add clicks (optional) to see your click-through rate and cost per click from the same numbers.

The result updates as you type. The formula box shows the calculation with your own numbers, and Copy result puts it on your clipboard for a report or a media plan.

CPM = ad spend ÷ impressions × 1,000

Example. A campaign spends $500 and gets 50,000 impressions. CPM = $500 ÷ 50,000 × 1,000 = $10. Each single impression cost one cent.

The same formula rearranged answers the other two questions:

Cost = CPM × impressions ÷ 1,000
Impressions = budget ÷ CPM × 1,000

• What will 200,000 impressions cost at a $7 CPM? $7 × 200,000 ÷ 1,000 = $1,400.
• How many impressions does $300 buy at an $8 CPM? $300 ÷ $8 × 1,000 = 37,500 impressions.

From impressions to people reached

Impressions count views, not people. Divide impressions by frequency (the average number of times each person saw the ad) to estimate reach. The 37,500 impressions above at a frequency of 2.5 reach about 15,000 people.

CPM, CTR and CPC together

If you know your CPM and click-through rate, you know your cost per click: CPC = CPM ÷ (1,000 × CTR). A $10 CPM with a 1% CTR gives 10 clicks per 1,000 impressions, so each click costs $1. The CPC calculator does this for you.

Most ad platforms sell impressions in an auction, so CPM is the price of attention at that moment. It moves with:

• Competition for the audience. The more advertisers bidding for the same people, the higher the CPM. Busy retail seasons push prices up across the board.
• The audience itself. Small, tightly targeted audiences and high-income markets usually cost more per impression than broad ones.
• Placement and format. Feeds, stories, short video and partner networks are priced differently, and so are search, display and video.
• The optimization goal. A campaign that asks the platform for purchases is shown to people more likely to buy, and those impressions cost more than ones bought for reach.
• How people respond to the ad. Platforms favour ads people engage with, so a stale or poorly matched ad can cost more to deliver.

Season alone moves prices a lot. Across more than $3 billion of Facebook ad spend, the all-industry average CPM over a recent 13-month window was $20.59, ranging from $16.47 in July to $24.26 in November: about 47% more for the same impressions in the run-up to the holidays.

Because of all this, a good CPM is the one that leads to an affordable cost per result. A $25 CPM that converts well can beat a $5 CPM that brings clicks nobody buys from. Judge CPM together with click-through rate, conversion rate and CPA, and compare it with your own past campaigns on the same audience and season rather than with a general average.

• Broaden the audience. Very narrow targeting competes for a small pool of people. Wider audiences give the platform more cheap impressions to choose from.
• Try more placements. Letting the platform deliver across several placements usually lowers the average CPM compared with one placement.
• Refresh creative. When frequency climbs, the same people see the same ad again, engagement falls and delivery gets more expensive.
• Plan around peak seasons. Run tests when auctions are quieter, and budget for higher CPMs in the busiest weeks.

Do not chase a low CPM for its own sake. Cheap impressions often come from placements or audiences that rarely buy. If your cost per purchase is on target, a rising CPM is not a problem to fix.

• Awareness campaigns are judged on CPM. When a campaign's goal is reach, Ad Autopilot judges it on CPM, cost per 1,000 people reached and delivery health, not on conversions it was never meant to produce.
• Saturation is detected in code. On Meta, once a campaign has at least 3 settled days and 5,000 impressions, the agent flags audience saturation when frequency reaches 3, or when it is 2.5 or more while CPM rises and click-through rate falls. It then proposes a fix, such as fresh creative or a wider audience, instead of just watching.
• Budget versus audience size. The agent turns your daily budget and recent CPM into expected weekly impressions (7 × daily budget ÷ CPM × 1,000) and divides that by the audience size from Meta's delivery estimate. Above 2.5 impressions per person a week, it flags the budget as too big for the audience before frequency actually climbs.