The Most Effective Ad Sizes

For web retargeting, there are 6 sizes Geobid has found to be the most effective. 4 of these sizes are optimized for “reach” (ie., reaching the most viewers by being shown on the most commonly available ad sizes on the Internet)

These 4 “reach” sizes are:

Mobile leaderboard- 320 x 50

Leaderboard- 970 x 90

Medium Rectangle- 300 x 250

Thin Skyscraper- 120 x 600

Wide Skyscraper- 160 x 600

The 5 “reach” sizes account for almost 90% of all the available ad inventory in a Real Time Bidding (RTB) auction. Because of this large amount of availability, the Cost Per Thousand Impressions (CPM) is relatively inexpensive (ie $1 to $3 per thousand impressions).

The 1 remaining recommended web size is in a much larger format. This size is:

Large Rectangle- 300 x 600

This “Billboard” size is readily apparent to viewers and is very effective at recapturing web visitors. It will have a higher CPM (ie. $3-$5 cost per thousand impressions), but it’s Click Through Rate (CTR) and View Through Rate (VTR) is higher, potentially resulting in a lower Cost Per Acquisition (CPA) of each desired conversion.

The following illustrates how each size appears on a visitor’s device:

Mobile leaderboard- 320 x 50

Leaderboard- 970 x 90

Medium Rectangle- 300 x 250

Thin Skyscraper- 120 x 600

Wide Skyscraper- 160 x 600

Large Rectangle- 300 x 600