A CPM calculator divides what you spent by the impressions you got, then multiplies by 1,000: CPM = (cost ÷ impressions) × 1,000. Enter any two of cost, impressions and CPM above and the calculator returns the third.
Spending $500 for 40,000 impressions, for example, works out to a $12.50 CPM.
CPM stands for cost per mille, which is Latin for "per thousand."
It is the price of showing your ad 1,000 times.
It does not tell you how many separate people saw it.
How to use the CPM calculator
You can solve for any one of the three numbers.
- Find your CPM: enter total cost and total impressions. Use this to check a campaign against a benchmark.
- Find your cost: enter a CPM and the number of impressions you want. Use this to budget a reach or awareness campaign.
- Find your impressions: enter a budget and an expected CPM. Use this to see how much delivery a budget buys before you launch.
Use the same date range and currency for every input.
If you mix a 7-day spend with a 30-day impression count, the result is meaningless.
The CPM formula, with worked examples
There are three versions of the same formula. Each one is just the other rearranged.
- CPM = (cost ÷ impressions) × 1,000
- Cost = (CPM × impressions) ÷ 1,000
- Impressions = (cost ÷ CPM) × 1,000
Example 1: how to calculate CPM
A Meta campaign spent $2,400 and served 160,000 impressions.
Divide $2,400 by 160,000 to get $0.015 per impression.
Multiply by 1,000 and the CPM is $15.00.
Example 2: how much will 500,000 impressions cost?
You expect a $13 CPM on YouTube and want 500,000 impressions.
Multiply $13 by 500,000 to get 6,500,000, then divide by 1,000. The campaign costs about $6,500.
Example 3: how many impressions does $1,000 buy?
With a $1,000 budget and a $20 CPM, divide $1,000 by $20 to get 50, then multiply by 1,000. You can expect roughly 50,000 impressions.
If CPM rises to $25, the same budget buys only 40,000 impressions.
Converting CPM to cost per click
If you know your CPM and your click-through rate, you can estimate cost per click.
CPC = CPM ÷ (CTR × 1,000). At a $15 CPM and a 1% CTR, that is $15 ÷ 10, or $1.50 per click.
Our CTR benchmarks show typical click-through rates by platform.
Things the formula does not account for
Impressions count every time an ad is shown, so one person seeing your ad three times counts as three impressions.
To see how many times the average person saw your ad, divide impressions by reach. That number is called frequency.
Platforms also count impressions in different ways. On the Google Display Network, Google offers viewable CPM (vCPM) bidding, where you only pay when your ads can be seen.
A vCPM and a standard CPM are not directly comparable.
CPM is an input, not an outcome. A low CPM with weak creative can still produce an expensive cost per purchase.
To connect the two, run your numbers through the CPA calculator and the ROAS calculator.
Real CPMs from the database
Benchmarks give you a range. Real accounts show how much that range moves.
Here is what advertisers in our archive have reported.
An advertiser whose post @SamPiliero shared saw a Meta ecommerce account's CPM drop from $50 to $15 after moving to the M3 structure.
Running that through the formula, the same $1,000 works out to 20,000 impressions before and about 66,667 after.
@runtraffic shared a YouTube video-ads snapshot at a $13.00 CPM for an ecommerce account.
That is a useful reference point if you are budgeting video reach on YouTube.
Low frequency is one sign that your CPM is buying fresh reach.
@runtraffic reported a $33.44 cost per purchase at a frequency of 1.06 on Meta cold-traffic ad sets.
That means almost every impression reached someone new.
CPM only matters through what it produces. @SamPiliero logged 1,238 purchases on $42.5k of spend (about $34 CPA) with creative packs across 64 ad sets.
CPM isn't shared for this account, so judge it by the CPA.
To see where your number sits, compare it with our Facebook CPM benchmarks.
For other channels, see YouTube ads costs and TikTok ads costs.
If your CPM is climbing, browse what lowered CPM in other accounts.
If you would rather have someone audit your account's delivery costs, we can match you with a media buyer who has done it before.