I was wondering if there are standard sizes which designers use when you want to reserve space for a web advert on their website design.
I’m aware of these sizes given by IAB http://en.wikipedia.org/wiki/Web_banner#Standard_sizes
Then there are also the Google Ad sizes.
I want to know which sizes are most commonly used by Web Designers when reserving space.
I’m not sure there really is a definitive answer to this, as it’s often up to the site on which you wish to display your ads, how their site is designed, and where in that design they place their ads.
The best thing to do is to ask the site which size(s) they prefer. Most companies will have some sort of “Media Guide” or documentation outlining the dimensions, format, file size, etc. that the ads should be.
If, for some reason, you can’t ask them, I would go with the Google sizes.
Google’s sizes have been somewhat of a benchmark for quite a few years now. I have been designing banners and ads for web use for 10+ years now and the Google sizes are by far the most common ones, though I have noticed the banner ads are starting to get wider, as websites also do.
As I previously stated, it’s best to ask first.