CPM is the price of being seen. It is what you pay for one thousand views of your ad, whether or not a single person does anything about it.
The name is Cost Per Mille, and mille is just the old word for a thousand. Say you spent 4,000 and your ad was shown 20,000 times. That is twenty lots of a thousand, so your CPM is 4,000 divided by 20, which is 200. Every thousand times your ad appears, it costs you 200.
Put in your own spend and how many times you were shown:
Here is the part that trips people up. A low CPM feels like a win, but cheap views shown to the wrong people are just a cheap way to waste money. A higher CPM in front of exactly the buyers you want can be the best money you spend all month. The price of being seen means nothing on its own, it only matters next to what those views turn into.
Three things move your CPM, and only one of them is about your ad. Narrow, wealthy, in-demand audiences cost more to reach than broad ones. The busy weeks before big sale days get crowded, so everyone pays more to show up. And a strong ad earns cheaper reach while a weak one quietly gets taxed. So when your CPM jumps, do not react to that number alone. A rising CPM in a busy season is normal, and the only question that matters is whether your cost per sale still looks fine. If it does, the CPM is a distraction.
CPM is the rent you pay on attention. Whether that attention was worth renting is a different number.
Sources
- Standard advertising definition. This page explains a universal metric, not a Meta-specific figure, so there is no benchmark or platform number to source. Any example numbers are illustrative and labelled as made up.
Last checked 8th August 2026. Next check due 15th August 2026. Every number on this page has a source and a date.