I would like to know how much CTR is considered good in Adwords. What about if it is between 4% and 5%.
You may wish to read Google's article on expected clickthrough rate, which is a metric that will tell you how your ads compare to others.
I can't vouch for the information in it, but this also seems to be a relatively comprehensive article on the topic: wordstream.com/average-ctr
'good' CTR is measured against your competitors. When you launch your ad Google will give you a quality score which will give you some idea on how relevant internet users see your advertisement compared to your competitors.
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I echo what Doodled said. It's measured against your competitors. Some queries simply have low ad CTRs as users tend to click more on organic search results or videos.