No, vodka is not usually around 40% alcohol by volume. On average, vodka is usually between 35-50% alcohol by volume, depending on the brand and type of vodka. Many brands of vodka are 40% alcohol by volume, but this is by no means the standard or average.
In fact, some brands of vodka are even higher in alcohol content. For example, a Polish vodka called Spirytus has an alcohol content of 96%! This is the highest alcohol content of any commercially available spirit.
In addition, many brands of vodka produce low-alcohol versions of their products that are often around 30% alcohol by volume. These are often referred to as “light” versions of vodka.
So, while 40% alcohol by volume is a common alcohol content for vodka, it is not the standard or average. There is a great deal of variation between brands and types of vodka, and the alcohol content can range from around 30-96%!