CPM, CPC and CPA Calculator
Turn ad spend, impressions, clicks and conversions into CPM, CPC, click-through rate, conversion rate and cost per acquisition.
How to calculate CPM, CPC and CPA
These five numbers follow a visitor from seeing your ad to buying. Each one divides your spend, or one step of the journey, by the step before or after it.
CPC = Ad spend ÷ Clicks
Click-through rate = Clicks ÷ Impressions × 100
Conversion rate = Conversions ÷ Clicks × 100
CPA = Ad spend ÷ Conversions
Worked example
A campaign spends $500, is shown 50,000 times, gets 1,200 clicks and 36 orders. The CPM is $10.00, the click-through rate is 2.40%, each click costs about $0.42, 3.00% of clicks turn into orders, and each order costs about $13.89 in ad spend.
How the numbers connect
CPA equals CPC divided by the conversion rate, so there are two ways to bring it down: pay less for each click, or turn more of the clicks you already get into orders. Improving your product page can lower your CPA as much as changing the ads.
CPM, CPC and CPA calculator FAQ
What is the difference between CPM and CPC?
CPM is what you pay for every 1,000 times your ad is shown, whether or not anyone clicks. CPC is what you pay for each click. A low CPM with a poor click-through rate can still mean an expensive CPC.
How do I calculate CPA?
Divide your ad spend by the number of conversions. $500 of spend that produced 36 orders is a CPA of about $13.89. CPA is also your CPC divided by your conversion rate.
What is a good click-through rate?
It varies a lot by platform, placement, audience and product, so there's no single good number. Compare each campaign with your own past campaigns on the same platform, and watch whether changes to the ad or audience move it.
Why can conversions be higher than clicks?
Some platforms count view-through conversions: orders from people who saw an ad but didn't click it. If your conversions are higher than your clicks, check which conversions your report includes.