Formula for getting data from week number (reverse WEEKNUM)

Looking for a formula that works basically like the WEEKNUM function in reverse in ISO format. So, if given 3/2007 (week 3, year 2007) it will return Jan 15, 2007 (Monday, first day in week 3 of 2007).

Not sure where to start. Any help would be appreciated.

The two formulas proposed above seem to provide exactly the same results (at least from 2017 to 2053).
However, these Excel ISO date manipulations have some particularities to watch for.

For testing, I filled Col A of a worksheet with the real dates from 2017-01-01 (Sunday of ISO week 1, 2016) to 2053-12-29 (Monday of ISO week 1, 2054).

Then,

col B: =ISOWEEKNUM(columnA)
col C: =TEXT(columnA,"yyyy")
Col D: =TEXT(columnA,"d")
Col E: =TEXT(columnA,"ddd")
Col F: =DATE(columnC,1,1)+(columnB - IF(WEEKDAY(DATE(columnC,1,1),2)<5,1,0))*7 - WEEKDAY(DATE(columnC,1,1),2)+1
Col G: =DATE(columnC,1,columnB*7-2) - WEEKDAY(DATE(columnC,1,3))

The issue is : the year column, calculated using the text function, is NOT ALWAYS equal to the "ISO week-numbering year" (i.e. the "year" portion of an ISO week reference).
In other words,

2018-12-31 is year 2018 but ISO week #1 (2019)
2019-12-30 is year 2019 but ISO week #1 (2020)
2024-12-30 is year 2024 but ISO week #1 (2025)
etc.

See below:
Clipboard01.png

I could not find a ISOYEARNUM function in Excel, which would give the quasi-year number linked with the ISOYEARNUM.
Seems at this point the only way is to use the formula below, from this post :

=YEAR(ColumnA-WEEKDAY(ColumnA,3)+3)

which is based on the particular properties of Thursdays under ISO-8601.

Hello mach128x,

Yes, I agree with what you say. Obviously the "ISO week number year" and the real year never align correctly, any date in the range 29th December to 3rd Jan can be in the "wrong" year. A far as I know there's no better way to get the correct year than that formula you found, have you answered your own question?