calculate date without holidays (only working days)

Thank you.

• Generate a calender including the possible date range from which holidays and weekend days are removed.
• To add working days, we merely look for the position in the List of working days that corresponds to then number of working days you wish to add.
• In your specific case, since the departure date is counted as Day 1, you must subtract 1 from the number of days you are looking for.
• Note that in the code below, I took your list of holidays and put in in a Query named HolyDay for access. But there is also code commented out that can download the holiday list for many countries from the web. (Using a Table for this will be much faster, however.
• I don't know if you will run into the same problem you had with the other solution

//Note optional Holidays parameter
//You can substitute a self-generated List of holidays, or use the website in the code to download a list
//  If you use the website, be sure to use a recognized country name
//If you are using holidays, you should separate this list and buffer the result for speed issues.
//  as written, it will download this list every time the function executes

(start as datetime, numDays as number, optional Country as nullable text) =>

let 
    adjNumDays = Number.RoundAwayFromZero(Number.Abs(numDays*7/5))*2,
    yrStart = Date.Year(start),
    yrEnd = Date.Year(Date.AddDays(start,adjNumDays*Number.Sign(numDays))),

//Create list of country specific Holidays
    holidays = HolyDays[holydays],

    /*yrs = {List.Min({yrEnd,yrStart})..List.Max({yrEnd,yrStart})},
     if Country = null then {} else    
        List.Accumulate(yrs,{},(state,current) =>
             let 
                Source=Web.Page(Web.Contents("https://www.officeholidays.com/countries/" & Country & "/" & Number.ToText(current))),
                Data0 = Source{0}[Data],
                DateCol = Table.SelectColumns(Data0,"Date"),
                fullDate = List.Transform(DateCol[Date], each Date.FromText(_ & " " & Number.ToText(current)))
            in   
                state & fullDate),*/

//all Working dates
//Generates a list of working dates in either Ascending or Descending order
//  based on the Sign of numDays
//  starting with the first working date after Start
    allWorkDates = 
        List.RemoveNulls(
            List.Transform(
                List.DateTimes(start, adjNumDays, #duration(Number.Sign(numDays),0,0,0)),
                    each if _ = start then _ 
                            else 
                                if Date.DayOfWeek(_)=Day.Saturday 
                                    or Date.DayOfWeek(_)=Day.Sunday 
                                    or List.Contains(holidays, Date.From(_))
                                then null 
                                else _)),
    addWorkDays = if numDays = 0 then start else allWorkDates{Number.Abs(numDays)}
    
in
    addWorkDays