Calculating number of complete and partial months

Please can anyone help me - I am trying to calculate the number of complete and partial monts in a period. I am using the formula (YEAR(E22)-YEAR(D22))*12+MONTH(E22)-MONTH(D22) but this is giving me 37 months for the period 14/05/2002 to 14/05/2005, I need this to give me 36 months and similarly for 1/07/2005 to 01/07/2005 I need to have the result "1" not zero. This is driving me mad!

try

=DATEDIF(D22,C22,"m")

Thanks but tried that, it only works out the no. of complete months

period 14/05/2002 to 14/05/2005, I need this to give me 36 months

similarly for 1/07/2005 to 01/07/2005 I need to have the result "1" not zero

I don't understand what you are trying to do.