What is the formula to find cost when given impressions and CPM?

The formula to calculate cost when given impressions and CPM (Cost Per Mille or Cost Per Thousand Impressions) is derived from the relationship between these variables. CPM represents the cost of 1,000 impressions. To find the total cost based on the given number of impressions, you would multiply the CPM by the number of impressions divided by 1,000.

This division is necessary because CPM is expressed per thousand impressions. When you have, for example, 5,000 impressions and a CPM of $10, you would calculate the cost as follows:

1. Divide the number of impressions (5,000) by 1,000 to convert to the number of thousands: 5,000 / 1,000 = 5.

2. Multiply the resulting number of thousands (5) by the CPM ($10): 5 x $10 = $50.

Thus, the formula can be summarized as CPM multiplied by (impressions divided by 1,000), which accurately calculates the total cost based on the number of impressions.