vCPM is viewable CPM: spend per thousand impressions that passed a viewability standard. An impression is one time the ad was served (sent to a page). A viewable impression is one that was actually on screen long enough, usually 50 percent of pixels for one second on display ads (the rectangles on websites). Let's take a shoe workshop in Mexico as an example. They make leather shoes and sell them online to Mexico and the United States. The shoe workshop spent $2,400 on banners that served 800,000 times, but only 400,000 were in view. The shoe workshop's raw cost per thousand impressions is $3. The viewable CPM is $6, because the denominator is half as large.

vCPM (Viewable CPM)

Q: How is vCPM different from eCPM?

Effective cost per mille (eCPM) uses all impressions in the denominator. An impression is one showing of the ad. Viewable CPM (vCPM) uses only viewable ones, meaning enough of the ad was actually on screen. Let's take a shoe workshop in Mexico as an example. They make leather shoes and sell them online to Mexico and the United States. The shoe workshop's $2,400 on 800,000 served impressions is a $3 effective CPM. The same $2,400 on 400,000 viewable impressions is a $6 viewable CPM. If half the shoe workshop's impressions never appeared on screen, viewable CPM will look roughly twice effective CPM. That is the point.

vCPM is how much you pay for one thousand times your ad was actually on screen long enough that someone could have seen it. vCPM stands for viewable cost per mille, and mille is Latin for thousand. The usual rule is half the ad on screen for one second, or two seconds for video. If you spend $6 and that happens 1,000 times, vCPM is $6. Ordinary CPM also counts ads that loaded off-screen.

Theodor Lindfors, Founding Marketer · September 12, 2026

Formula

vCPM = (ad spend / viewable impressions) × 1,000

How to calculate vCPM

Let's take a shoe workshop in Mexico as an example. They make leather shoes and sell them online to Mexico and the United States. The shoe workshop has dozens of styles, colors, and sizes. It buys banner ads on websites, the rectangles that sit in sidebars, article bodies, and at the bottom of pages.

An impression is one time the ad was sent to a page. That can happen below the fold (the part of the page you cannot see until you scroll). Viewability asks whether enough of the ad was actually on screen. The usual MRC-style bar (the Media Rating Council's common standard) is 50 percent of pixels in view for 1 second on display, or 2 seconds on video. A viewable impression passed that bar.

The shoe workshop spent $2,400. The banners were served 800,000 times. Only 400,000 of those were viewable. Divide spend by viewable impressions, then multiply by 1,000. 2,400 divided by 400,000 is 0.006. Times 1,000 is $6. That is the shoe workshop's viewable CPM (vCPM). The same $2,400 spend on all 800,000 served impressions is a $3 CPM or eCPM (effective cost per mille). The shoe workshop thought it was paying $3 per thousand looks. For looks that actually happened, it was $6.

Why vCPM matters

You can buy cheap cost per thousand impressions on inventory nobody sees. An impression is one showing of the ad. Let's take a shoe workshop in Mexico as an example. They make leather shoes and sell them online to Mexico and the United States. The shoe workshop's $3 raw cost per thousand impressions looked like a deal until half the banners loaded at the bottom of long articles and never scrolled into view. Viewable CPM (vCPM) is how you stop paying for ads that never had a chance. Programmatic teams (teams that buy ads through automated auctions) use viewable CPM as the honest price.

How to read vCPM

Let's take a shoe workshop in Mexico as an example. They make leather shoes and sell them online to Mexico and the United States. A viewable CPM (vCPM) close to ordinary CPM (cost per thousand impressions) means most impressions were viewable. An impression is one showing of the ad. A large gap, like the shoe workshop's $3 raw cost per thousand versus $6 viewable CPM on the $2,400 banner spend, means the placement is the problem, not the bid. Do not fix the gap by raising bids on those unseen banner placements. Drop the placements that never come on screen, then look at viewable CPM again.

Common vCPM mistakes

These mistakes show up when a shoe workshop in Mexico that sells leather shoes online treats viewable CPM as a score to maximize, rather than an honest price for ads that were actually on screen.

Treating 100% viewability as a goal. Viewability means enough of the ad was on screen, usually 50 percent of pixels for one second on display. Some formats never hit 100%. A sticky footer on a short page still gets cut off, including for the shoe workshop's banner.
Mixing Active View (Google's viewability tool), MRC (Media Rating Council) standards, and platform viewability into one viewable CPM (vCPM). The shoe workshop picks one standard and labels the slide, then divides the $2,400 banner spend by that one count of viewable impressions.

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