When did world war 2 start

Did you even Google it? A simple 10 second Google search returned this

start of world war II - Google Search

I am sure he did not search it at all, J.

Here is a timeline for WWII in Europe:
The History Place - World War Two in Europe Timeline

If you cannot follow the timeline, go to this:
A Brief History of World War II

Yeah, those timelines were in the Google search I believe.

When you critically think about it, there are various answers. One country declaring war on another does not constitute a 'world' war, thus britain declaring war on german [and the axis] is not necessarily the beginning of things. As the title suggests, it was a war involving [not all] but a large part of the world. Therefore the only suggestible answer is the year 1939 [when the majority of countries declared war on one another]. Sound silly? Think about it...

Germany invaded Poland on September 1,1939. England and France declared war on Germany on September 3rd.;)

As usual, folks are putting the war in terms of Europe. There are those who will argue that the World war started in either 1933 or 1937 with the Japanese attacking the Chinese.

If you focus on Asia, World war II began in September of 1931 when Japan invaded Manchuria.