eCPM
Paid MediaAlso: Effective CPM · Effective Cost Per Mille
Quick definition
Effective CPM (eCPM) is the cost per thousand impressions you actually achieved, worked backwards from total spend and total impressions. Unlike CPM, which is a rate you're quoted upfront, eCPM is a result you calculate after the campaign runs, and it works no matter which pricing model you paid under.
A low eCPM only matters if the impressions came from an audience likely to convert. Read it next to conversion rate or CPA on the same campaign before deciding it's good.
How it varies across Australia
eCPM varies by platform, placement and audience far more than most Australian advertisers expect. Programmatic display typically produces the lowest eCPM, premium social placements and connected TV sit well above it. The number only means something next to your conversion rate and CPA on the same campaign.
Compare paid media efficiency across Australian industries →What it actually means
eCPM solves a real problem. Different ad campaigns get sold on different pricing models: cost per click (CPC), cost per view, cost per action, flat CPM. Comparing performance across those models is like comparing prices quoted in different currencies. eCPM converts everything back to one common unit: cost per thousand impressions, calculated after the fact.
The calculation is simple. Take total cost, divide by total impressions, multiply by 1000. It doesn't matter if you were billed on clicks or actions. eCPM tells you what those impressions cost you in the end, regardless of how the invoice was structured.
This matters because a campaign with a fantastic click-through rate (CTR) and a terrible eCPM can still be a bad buy, and a campaign with a mediocre CTR and a brilliant eCPM might be quietly efficient. eCPM sits alongside CPA, ROAS and conversion rate as one more lens, not a replacement for any of them. On its own it tells you almost nothing about whether the campaign worked. Next to those other numbers, it tells you whether the media itself was cheap or expensive relative to what you got for it.
eCPM is the great equaliser. It doesn't care whether you paid per click, per view or per action. It tells you what every thousand impressions actually cost.
How to calculate it
eCPM = (Total cost ÷ Total impressions) x 1000
Worked example. You spent $800 on a campaign billed per click, and it generated 200,000 impressions along the way. eCPM = ($800 ÷ 200,000) x 1000 = $4.00. Every thousand impressions effectively cost you four dollars, even though you never paid for impressions directly.
The Australian context
The Australian ad market has fewer buyers bidding in most programmatic auctions than the US or UK, which tends to push eCPM lower on generic inventory but higher on premium placements where demand concentrates around a small pool of advertisers. Connected TV and premium publisher inventory in Australia often carry higher eCPM than equivalent US placements simply because there's less supply.
Where people get this wrong
eCPM vs CPM
| eCPM | CPM | |
|---|---|---|
| What it is | A rate agreed before the campaign runs | A result calculated after the campaign runs |
| Pricing model | Applies specifically to impression-based buys | Applies to any pricing model, converted to a common unit |
| When you know it | Upfront, in the media plan | After delivery, from actual spend and impressions |
| Best use | Negotiating and comparing media rates | Comparing actual efficiency across campaigns and platforms |
Related terms
Common questions
What's the difference between CPM and eCPM?
CPM is the rate you're quoted or negotiated before a campaign runs, specific to impression-based pricing. eCPM is calculated after the campaign runs, from actual total cost and total impressions, and works regardless of how you were billed.
How do I calculate eCPM?
Divide total cost by total impressions, then multiply by 1000. This works whether you were billed per click, per action or per impression, because eCPM converts everything back to a cost-per-thousand-impressions basis.
Is a lower eCPM always better?
No. A low eCPM can mean cheap, low-quality inventory that never converts. Always read eCPM alongside conversion rate or CPA. Cheap impressions that don't convert cost you more in the end than pricier impressions that do.
Why would I use eCPM instead of just comparing CPA across campaigns?
eCPM isolates the cost of the media itself, separate from how well your creative or landing page converted. It helps you diagnose whether a poor CPA is a media-buying problem or a conversion problem further down the funnel.
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About New Rebellion
New Rebellion is a marketing intelligence consultancy. We build tools, score Australian businesses on how their marketing actually performs, and publish Debrief every day. This dictionary is part of how we work in the open.
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