One Size Does Not Fit All: An Analysis of Ad Sizes on the Google Display Network

As a data analyst at Click Rain, I was curious to see which ad sizes are the most successful on the Google Display Network. In order to study this, Google AdWords data from five of our clients was collected to study ad sizes compared to click-through rates, impressions, and cost-per-click.

How often are my ads clicked on?

A common success metric for ads is click-through rate. Recall that click-through rate is the number of clicks that your ad receives divided by the number of times your ad is seen, expressed as a percentage (Google). The graph below summarizes the click-through rate among different ad sizes.

Click-through rate by ad size


The ad size with the highest click-through rate was 970x250 (pixels), which had a click-through rate of about .55%, followed by ads of the size 336x280, which had a click-through rate of .46%. Ads of the sizes 300x600 and 300x250 both had click-through rates of .28%.

Does this mean that you should invest all of your time and money into displaying ads of the size 970x250? Probably not. I also wanted to investigate which ads are seen most often and which ad sizes are the most cost-effective.

How often are my ads seen?

Next, we’ll compare click-through rate to the average number of impressions for each ad size. Recall that the number of impressions is a count of the times your display ad was shown on the Google Display Network (Google). At Click Rain, we not only want your ads to be clicked on, but we also want them to be seen across the Google Display Network. The following graph shows the average impression count of each ad size, compared to click-through rate.

Click-through rate and impressions


What does this tell us? Although ads that were sized 970x250 had the highest click-through rate, they had one of the lowest impression counts at an average of 2,225 impressions. So although they had a high click-through rate, they were seen less often than ads of other sizes, so you may not want to invest all of your money into ads of this size.

Ads sized 336x280 and 300x600 had average impression counts of 16,811 and 14,274, respectively. They are seen regularly and have fairly high click-through rates. Ads that were sized 300x250 had a slightly above average click-through rate and they have the highest count of average impressions at 64,522.

How much will these ads cost?

Last but certainly not least, which ad size was the most economical? We want our clients to be investing in ad sizes that are both affordable and have high performance. The graph below shows the average cost-per-click compared to ad size and click-through rate.

Click-through rate and cost-per-click


Surprisingly, ads which were sized 970x90 cost about $1.50 a click and had a below average click-through rate, so they may not be worth investing in. Ads sized 970x250 cost about $1.15 per click and ads sized 300 x 250 costed about $1.17 per click. Ads sized 336 x 280 or 300x600 are a steal, with above average click-through-rates and cost-per-click around $0.86 and $0.88, respectively.

So which ad sizes should I invest in?

You might see different statistics for your ads across the Google Display Network. However, our results show that ads of certain sizes may not be worth investing in. For example, ads sized 970x90 come with a larger price tag and do not perform that well. Ads sized 970x250 may be worth an investment to see a high click-through rate and those sized 336x280 have a high click-through rate, an average impression count, and are also affordable.

Want us to analyze your ad campaigns? Seeing different results in your industry? We'd love to hear from you