Google is showing answers for calculation, unit conversion, and local time queries without any search results on mobile devices.

Many of you probably still remember the zero search results experiment Google conducted in March:

Update! We have enough data and feedback — which is appreciated — to conclude that the condensed view experiment should stop for now. The team will look at improving when and how it appears. — Danny Sullivan (@dannysullivan) March 20, 2018

Danny Sullivan of Google confirmed that they were testing the 0 results SERPs globally for the same types of queries we are seeing now. In a later update, he said that they had collected enough data and feedback and the experiment had been stopped until certain improvements are made. It looks like the improvements have been made and the results are available again.

I compared the results I see now with the results and complains we saw in March looking for changes that may have been made. I have been able to find 2:

Zero result SERPs are now only available in mobile search. In March, they were also available on desktop;

Google seems to only display 0 results when there is very little ambiguity. For example, “5+5” returns 0 results, while “2+2” (which is related to some entities) returns a regular SERP;

No ads are displayed for zero result SERPs.

I am able to replicate this in different browsers on different mobile devices which is often an indicator of a rollout, but this may also be another global experiment.

Update: Google confirmed that this has been rolled out.