Converting drop frame timecode to non drop frame timecode, and vice versa

[picrade]

Given a drop frame timecode, in hh:mm:ss:ff , what is the formula to convert it to non drop frame timecode?
Conversely, given a non drop frame timecode, what is the formula to convert it to drop frame timecode?

I know the explanation, i.e., drop 2 frames every minute except 0, 10, 20, etc.
But I can't turn it into straightforward formulas.
And by straightforward formula I mean somehing that I can program in an Excel spreadsheet.
Or, is there an Excel spreadsheet that already does these conversions?


P.S. There may be other programs that will do these conversions, but for my purpose it's got to be an Excel spreadsheet.

[manono]

Hi-

I don't know anything about Excel or if this helps at all or not, but to go from 30fps to 29.97fps you divide by 1.001.

30000/1001=29.970030