CPM, CPC and flat fee, on one scale
Ad sellers price the same thing three ways — per thousand impressions, per click, or one fixed fee — so that offers are hard to compare. Enter each quote and the click rate you expect, and every price comes out per click and per thousand.
CPM deal, per click
$1.11
CPC deal, as a CPM
$18
Flat fee, as a CPM
$15
Flat fee, per click
$1.67
What this means
At a 0.90% click-through rate, the CPM deal is cheapest per click ($1.11). The ranking turns on the click rate, so change it and watch the order move.
How it works
A CPM becomes a cost per click by dividing it by the clicks a thousand impressions produce: CPC = CPM ÷ (1,000 × CTR). A CPC becomes a CPM the other way round.
A flat fee is divided by the impressions the seller says it buys. If the seller will not say, the fee cannot be compared at all — which is worth knowing before you pay it.