Starting in A1 I have
Reagent Stock date Shelf life Flag
AgNO3 1-Jun-08 270 Out of date


The formula in D2 is =IF(B2+C2TODAY(),"","Out of date")
Additionally (or as an alternative) sue conditional formatting to make the
row red
Select A2:D2 ( when you have more select A2:D(last row)
In Conditional Formatting use:
Formula Is : =$B2+$C2<TODAY() and set format to suit your need

best wishes
PS I have no idea how long a solution of silver nitrate would last, even
thought I was a chem prof!
--
Bernard V Liengme
Microsoft Excel MVP
http://people.stfx.ca/bliengme
remove caps from email

"haem" wrote in message
...
I would like to set up a spreadsheet for reagents that will automatically
flag if a reagent is past its expiry date