This is a Google-specific trick. If you have a piece of information in one frame of reference, but want to know it in another, you can ask Google if it knows the answer, and chances are it will.
To do this, enter the search pattern “X in Y”, where X is the piece of information you have (for example a weight), and Y is the unit or format you want the information in. For example, “4kg in oz”, “3m in feet”, or “2 pints in litres”. Very useful in this part of the world where mixed usage of metric and imperial units is common.
Better yet, this trick also works for less obvious stuff like currency conversion.
Google’s documentation of this feature is delightfully vague, so I’m only discovering what this feature can do by trial and error. If you figure out something particularly nifty it can convert, please comment below and share the wisdom.