Is "to" inclusive in “I worked at company X from April 2012 to April 2013”? [duplicate]

I have a question about the use of the word to as a time proposition. Is to inclusive in the following sentence?

I worked at company X from April 2012 to April 2013.

It's ambiguous.

Some may read it as including April 2013, others may not. I'd probably read it as inclusive.

American English uses the inclusive word through:

• I worked at company X from April 2012 through April 2013.

For unambiguous British English, add extra wording:

• I worked at company X from April 2012 to April 2013, inclusive.

• I worked at company X from April 2012 through to April 2013.

• I worked at company X from April 2012 up to and including April 2013.