As of December 4, 2017, you can now create Meta Descriptions well over the previous 160 character limit. I have now run multiple tests, and while Google can indeed show its own Snippet in search results, you can influence the snippet shown by using a large, 300+ character meta description just like this one.
Update 12/6/2017: After further testing on mobile, I am now recommending a 300 character meta description. See my article here.
Update 12/4/2017: The maximum sized Meta Description I’ve personally been able to “force” Google to display in search as a Snippet is 302 characters. As noted below, mobile searches are “not always” nearly as long. A creative meta description could consist of 2 sentences, one which is 160 characters, and the second which is up to 140 more:
My test (on desktop)
I tend to put the most accurate and concise description of a page at the very top of an article, just like I did on this page. I do this for several reasons (most of the time). For my test, I created a page (this one) and copied the top paragraph in to my content management system’s back end as a Meta Description. I published the article and searched for it and ta-da, my 300+ character meta description displayed perfectly in Google’s search results. In this case, I intentionally left the “4” out of the date in the Meta Description to be sure Google was using the Meta for the Snippet. They did.
A recent change
I just published the article “Google Ignoring Meta Descriptions and Enlarging Snippets“. That’s because as of November 2017, Google has suddenly been displaying huge snippets in search results. They are also ignoring people’s meta descriptions and crafting their own snippets, especially if they think their snippet will be a more accurate description of a page than your meta description.
Meta Description vs Snippet
If you are confused by this terminology, you are not alone.
You can manually edit a page’s Meta Description. And in many cases, that is what is shown in Google’s search engine results pages. However, the technical name for what is displayed is a Snippet.
Ok, here is the screenshot (and yes this site gets indexed very quickly). I’ll have to do a little more testing with this as it appears that my snippet was chopped right at 300 – 302 characters:
This isn’t a guarantee
Google has been replacing snippets in search results for at least 7 years now. Just because you have set a Meta Description does not mean that Google will use it.
Tips going in to 2018 and further testing
If you are seeing funky snippets in search results, try making a neat, concise and accurate 240 – 300 character Meta Description for your pages, fetch and render them and see if your snippet improves.
I am personally now playing with meta descriptions which explain everything in 160 characters, and then adding onto that with 140 more. That’s because Mobile search results are frequently still displaying 160 (but can display ~300):