### Title

Week of the Year

### Post

FM function WeekOfYear return wrong value for year 2010 for example.

1 Jan 2010 is week 53 (year 2009) not week 1 and 8 Jan 2010 is week 1 not 2.Normally the 1st week of the year is the week when 1 Jan is after Wednesday.Or I'm wrong?

No - this isn't what is expected.

Look here: http://www.onlineconversion.com/day_week_number.htm

That is correct. That is how world look on things.

When I say - let's plan meeting on the second week 2010, the everybody looking on every average day planner see dates 11-17 Jan 2010 NOT 4-10 Jan 2010 - as FM calculate.

So - calculations must be added to this function OR may be easier is write a new one.

In Help is discovered full useless of this function in any WeekOfYear standard: FM calculate weeks from 1 to 54 for every year and don't care about the day of the 1/1/Year.

This is the first case where I find out useless of FM function.

I write all this just to say - be careful and don' trust to the FM calculation result in this particular case. Only this.

I believe the WeekOfYear() function returns the same results as the WEEKNUM function in Excel.

Whether that is useless or not is a matter of opinion.

I certainly agree that one should read very carefully what each function does.