eCPM is effective cost per mille - the revenue a publisher earns per thousand filled impressions, normalised across whatever pricing models produced it. It lets you compare a CPC partner with a revenue-share partner on a single number.

What is the difference between eCPM and CPM?

CPM is a price an advertiser agrees to pay. eCPM is a result a publisher measures after the fact. They are the same unit viewed from opposite sides of the transaction, which is why comparing your eCPM against published CPM floors is a fair check.

Does fill rate change my eCPM?

Not directly - eCPM is measured on filled impressions only. But fill rate decides how many of your ad requests ever reach that eCPM, so it changes your total revenue and your RPM per request. Both are shown above.

It varies by GEO, format and traffic quality more than by anything else. As a floor, advertisers on TrafficSigma pay from $1.00 per thousand for Tier-3 pop traffic and from $2.00 for Tier-1. If your eCPM on comparable traffic is below that, it is worth testing another demand source.

Why is my eCPM lower than the CPM advertisers pay?

Every intermediary between the advertiser and you takes a share, and unsold requests dilute the average. A large gap is normal; a gap of most of the CPM is not.

How do I raise my eCPM?

Raise fill first - it is usually the cheapest win - then improve placement and traffic quality, then add competing demand so partners have to bid against each other for the same impression.

eCPM Calculator

For publishers. Enter any two of revenue, impressions and eCPM and this calculator solves the third, factors in your fill rate, and tells you straight away whether your inventory is earning what advertisers pay for traffic like it. Benchmarked against the CPM floors TrafficSigma publishes to buyers.

Compare against a GEO

Loads the average pop CPM advertisers pay us in that country, so you can see the gap. Every figure stays editable.

Revenue

What you earned from this inventory over the period.

Filled impressions

Ads actually served and paid for. Not ad requests - see the fill rate below.

eCPM

Effective earnings per thousand filled impressions. Leave this to be solved.

Fill rate

Share of your ad requests that returned a paid ad. Under 100% means requests went unmonetized.

Enter any two of revenue, filled impressions and eCPM - the third is solved automatically. The field you touched least recently is the one that moves.

What your inventory is earning

Revenue of $1,000.00 on 1,000,000 impressions is an eCPM of $1.00. That clears our $1.00 Tier-3 pop floor but sits under the $2.00 Tier-1 floor, and Tier-1 traffic should be earning more.

At 85% fill you are serving 1,176,471 ad requests to deliver those impressions and losing 176,471 of them. Filling every request at the same eCPM would be worth $1,176.47, which is $176.47 more than you make today.

Fill rate and the money behind it

Ad requests needed: 1,176,471
Unfilled requests: 176,471
Revenue at 100% fill: $1,176.47
Left on the table by fill rate: $176.47
RPM per ad request: $0.85

eCPM, and the fill-rate trap

eCPM is what you earned per thousand impressions, whatever pricing model produced it. A CPC deal, a revenue share and a fixed CPM buy can all be reduced to an eCPM, which is what makes it the only fair way to compare two demand partners.

The trap is that eCPM is calculated on FILLED impressions, not on ad requests. A partner quoting a $3.00 eCPM at 40% fill earns you less than one quoting $1.50 at 95% fill, because more than half your traffic came back with nothing to show. The panel above converts your eCPM into an RPM per ad request, which is the number that actually lands in your account.

Once you know your real per-request RPM, compare it with what advertisers pay. TrafficSigma publishes its buy-side floors openly: $1.00 per thousand for Tier-3 pop inventory, $2.00 for Tier-1, and $3.00 for domain redirect. If your eCPM sits well under the floor for your traffic tier, somebody in the chain is keeping the difference.

The eCPM formula

eCPM = (revenue / filled impressions) x 1,000
Revenue = (filled impressions / 1,000) x eCPM
Ad requests = filled impressions / fill rate
RPM per ad request = (revenue / ad requests) x 1,000

eCPM calculator FAQ

What is eCPM?: eCPM is effective cost per mille - the revenue a publisher earns per thousand filled impressions, normalised across whatever pricing models produced it. It lets you compare a CPC partner with a revenue-share partner on a single number.
What is the difference between eCPM and CPM?: CPM is a price an advertiser agrees to pay. eCPM is a result a publisher measures after the fact. They are the same unit viewed from opposite sides of the transaction, which is why comparing your eCPM against published CPM floors is a fair check.
Does fill rate change my eCPM?: Not directly - eCPM is measured on filled impressions only. But fill rate decides how many of your ad requests ever reach that eCPM, so it changes your total revenue and your RPM per request. Both are shown above.
What is a good eCPM?: It varies by GEO, format and traffic quality more than by anything else. As a floor, advertisers on TrafficSigma pay from $1.00 per thousand for Tier-3 pop traffic and from $2.00 for Tier-1. If your eCPM on comparable traffic is below that, it is worth testing another demand source.
Why is my eCPM lower than the CPM advertisers pay?: Every intermediary between the advertiser and you takes a share, and unsold requests dilute the average. A large gap is normal; a gap of most of the CPM is not.
How do I raise my eCPM?: Raise fill first - it is usually the cheapest win - then improve placement and traffic quality, then add competing demand so partners have to bid against each other for the same impression.

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