Unfortunately my strength with Excel is weak, and I'm not entirely sure what to search for in general... I have a spreadsheet with a series of dates in Row 1 (with the exception of A1), data corresponding to the date in rows 2-12, and then a series of formulas below that. The dates are not completely consecutive; they correspond to "weekdays," and as such exclude weekends and holidays. I'd like to track certain changes over certain time periods, such as 1 day, 1 week, 1 month, etc. Here's the question: if the date in the column is, say, 08/31/2010, and I want to have Excel select a cell from a column one month prior, is there a way to phrase that in a formula? (i.e., it would select a cell from the column starting with 07/31/2010, or, since that was a Saturday and isn't in the chart, select from the row starting with 07/30/2010 instead). The same question applies to 1 week prior, or 1 year prior, for that matter. I'm suspecting that this is either significantly easier or significantly more complicated than I think it is; either way, I'd appreciate help, or at least alternative suggestions.